State of the art on Mugil research - MUGIL PROJECT - Home€¦ · In order to use of a species such...

INCO-CT-2006-026180 1 MUGIL Deliverable 1 - January 2007

DELIVERABLE 1

MUGIL

Main Uses of the Grey mullet as Indicator of Littoral environmental changes

2006 - 2009

December 2006

Homepage: mugil.econumeric.info Coordinator: J. Panfili (IRD)

Summary This synthesis highlights Mugil cephalus research conducted in the fields of population genetics, life history traits, migrations and biomarkers. The economic importance of this species to global fisheries is also stressed and future perspectives given.

European Commission

INCO-CT-2006-026180

MUGIL

State of the art on Mugil research J. Panfili, C. Aliaume, P. Berrebi, C. Casellas, C.W. Chang, P.S. Diouf, J.D. Durand,

D. Flores Hernández, F. García de León, P. Lalèyè, B. Morales-Nin, J. Tomás, W.N. Tzeng, V. Vassilopoulou, C.H. Wang, A.K. Whitfield 1,2,3

1 Addresses at the end of the document 2 The MUGIL Deliverable 1 follows the first MUGIL seminar held in Dakar (Senegal); 2-4 November 2006 (see Annex). 3 Image on cover: www.fao.org


Contents

Page

1. INTRODUCTION ....................................................................................................................................... 3 2. MUGIL CEPHALUS FISHERIES.............................................................................................................. 4

2.1. NORTH MEDITERRANEAN FISHERIES .................................................................................................... 4 2.2. MAURITANIAN FISHERIES ..................................................................................................................... 5 2.3. SOUTH AFRICAN FISHERIES................................................................................................................... 6 2.4. TAIWANESE FISHERIES.......................................................................................................................... 6 2.5. MEXICAN FISHERIES ............................................................................................................................. 7

3. POPULATION GENETICS STUDIES..................................................................................................... 8 3.1. THE MUGILIDAE FAMILY PHYLO-GENETICS .......................................................................................... 8 3.2. POPULATION STRUCTURE AND POPULATION GENETIC DIVERSITY ......................................................... 8

4. LIFE HISTORY TRAIT STUDIES......................................................................................................... 10 4.1. AGE ESTIMATION AND GROWTH.......................................................................................................... 10 4.2. REPRODUCTION .................................................................................................................................. 12

5. MIGRATION IN THE LIFE HISTORY CYCLE ................................................................................. 12 5.1. EGGS AND LARVAE – MARINE ENVIRONMENT .................................................................................... 13 5.2. RECRUITS – ESTUARIES, LAGOONS AND CONTINENTAL FRESHWATER ENVIRONMENTS....................... 13 5.3. ADULTS – MARINE ENVIRONMENT ..................................................................................................... 15

6. BIO-INDICATOR STUDIES ................................................................................................................... 16 7. CONCLUSIONS........................................................................................................................................ 17 8. REFERENCES .......................................................................................................................................... 17 9. AUTHOR ADDRESSES ........................................................................................................................... 21 10. ANNEX.................................................................................................................................................. 22


1. Introduction The particular status of estuaries, deltas and lagoons in coastal areas, located at the interface

between sea and river influences, results in highly variable environmental and ecological conditions that shift over space and time. The combined effects of climatic changes and human activities have tremendous consequences on these ecosystems. The conservation of these environments is one of the biggest challenges for humanity. In order to achieve an integrated management, researchers, ecologists and managers try to select relevant indicators, which could be used as tracers of the state of estuarine areas. These indicators are generally chosen among living species or physicochemical parameters or a combination of both.

Among the fish species living in estuaries, very few occupy these ecosystems in more than one oceanic region. However, there is one particular species, Mugil cephalus Linnaeus 1758 (Mugilidae), which is found worldwide and is cosmopolitan in almost all tropical coastal estuarine zones, but also in temperate ones (Fig. 1). This species is able to live and reproduce in widely different habitats. The mechanisms which are involved in this process are poorly known or are studied separately in each area. This abundant species, and related taxa of the same family, are very important for the fisheries, especially in developing countries (see below). Mugil cephalus is able to live in environments subject to pollution or in environments with highly variable salinity levels (from freshwater to hyperhaline, > 70 psu). It reproduces and grows in a wide variety of conditions but the mechanisms which are involved in these processes are poorly known. Several life history traits and physiological characteristics have been studied separately in different areas of the world. A number of questions arise from the adaptive capability of this species in contrasting situations:

• Is M. cephalus unique or integrated in a species complex? • What is the degree of connectivity between populations (gene flow and migration)? • At the individual level, what are the most stimulated genes for acclimatisation to widely

different habitats (e.g. to hyperhalinity or to pollution)? • At the population level, what are the life history trait variations and/or the physiological

characteristics involved in survival (or adaptation to) in the different environments?

In order to use of a species such as Mugil cephalus as an indicator of the state of coastal ecosystems, more detailed information on the biology of this species is still needed at different level of expertise. This first report of the MUGIL project (INCO-CT-2006-026180) gives a "state of the art" assessment of research on M. cephalus, but also on related mugilid species, at four different levels: population genetics, life history traits, and migration and biomarker studies. It also gives information on the fisheries of this species in different parts of the world.

Figure 1. Distribution area of Mugil cephalus (Mugilidae). Source: www.fishbase.org


2. Mugil cephalus fisheries The mugilids are a widely exploited fish family with target species depending on region. Adults

are targeted by small scale and recreational fisheries while larvae are captured for aquaculture in some countries. The commercial importance of mugilids depends on the country, ranging from much esteemed in Taiwan, Tunisia and Egypt to being of little value in some parts of Spain, Greece and France.

The total world production of mullet species (fishery and aquaculture) is important by weight and an increasing tendency was evident from 1950 to 2004 (data source: FAO). Among mullet captures, M. cephalus landings are also important by weight and increased significantly since the mid-90's (Fig. 2). They represent these days almost half of the total mullet captures (all species). These data probably are only indicative because the landings are reported in many areas as mugilids and without specification on the species. Besides the variable commercial value of the fish, other products such as roe are valuable and highly appreciated. In Taiwan, the muscular stomachs are regarded as a delicacy.

The fishery targeting mugilids is not very selective and in general captures several species together. As an example, in a Majorcan coastal lagoon (Spain), M. cephalus was captured only in 65% of the gill net operations directed to sample the species, while Liza sp. was present in all samples.

Most mugilid fisheries operate in coastal lagoons and estuaries. Some of these, such as in Africa are targeting juvenile or immature fish, while in other areas the post larvae are captured for aquaculture. For instance the larvae in Taiwan are cultured for gathering roe and those in the Ebro Delta (Spanish Mediterranean) are exported to Italy where the fish has a high value. Five different examples of mullet fisheries are described hereafter: the Mediterranean, the Mauritanian, the South African, the Taiwanese and the Mexican fisheries.

2.1. North Mediterranean fisheries

Within this area, there are few data on fishing effort and Mugil captures due to the lack of reporting on landings, the mix of captured species and the direct sale of catches. For instance, data collected in the southern part of Spain are very irregular (Fig. 3) and probably do not represent actual catch fluctuations. There are also fisheries in some lagoons and estuaries for which data are not available.

In Greece there are 72 lagoons covering approximately 55000 ha (Kotsonias 1984). All of the lagoons are part of the public domain, and are rented out by the State to individuals or cooperatives for fishing. This fishery targets migrant fish entering from the sea, such as grey mullets (Mugil spp.), gilthead (Sparus aurata), sea bass (Dicentrarchus labrax), European eel (Anguilla anguilla), sole (Solea vulgaris) and the exploitation process varies, depending upon the lagoon, the seasons, and local practice. At a regional scale, the lagoon fisheries play an important role in both socio-economic and cultural aspects. One of the most important fish species for lagoon fisheries is Mugil cephalus,

Figure 2. Total world captures for the species Mugil cephalus (Data source: FAO, www.fao.org).


primarily due to its relatively high commercial value as an edible fish and because of using the mature ovaries of females for the production of dried salted roe, a well-known delicacy in the Mediterranean area. Two peaks in M. cephalus landings from fish barrier traps of the Messolongi-Etoliko lagoon complex are observed; the first peak is from early August to late October and corresponds to the species’ spawning migration to the sea, and the second peak is during November and December, when this species conducts an inshore migration (Katselis et al. 2003, Katselis et al. 2005). Although official landings in Greece record all species of mullet together (Anonymous 2001), catch data of fish from the wharf at Messolonghi for the period 1988 to 2002 indicated mean annual landings of M. cephalus at approximately 14.9 tons (±0.9 S.E.).

Although total annual catches of M. cephalus in the Messolonghi-Etoliko complex do not show any particular trend during recent years, it is reported that total annual fish catches have decreased from 1500-2000·tons in the 1960s to 1300-1500·tons in the 1990s (Katselis et al. 2005). Moreover, Koutrakis (2000) stated that lagoons of northern Greece displayed low productivity, and in recent years fish catches have further decreased, mainly due to pollution effects. Decreasing trends of lagoon catches in Greece, as well as the fact that lagoon fisheries are based on a practice that impacts the life cycle of migratory species by removing potential spawners from the spawning stock, underline the necessity for integrated management of lagoon fishing activities. The latter requires the availability of sound scientific information aimed at clarifying various aspects concerning life history strategies of the various species inhabiting lagoons.

2.2. Mauritanian fisheries

The information is included in an IUCN report (Bernardon & Vall 2004). Mugilids are the primary group of species in terms of fisheries importance, with landings estimated above 14000 tons annually. This represents 18% of total landings, 50% of which comprise Mugil capurii and 20% Mugil cephalus. The landings in the Banc d'Arguin National Park are almost exclusively M. cephalus (98%) and represent 3% of the total landings of mullet in Mauritania. By-catches of mullet by the pelagic trawlers are estimated at approximately 15000 tons per year. The economic impact of the mullet fishery in Mauritania is extremely high, with 20% of the total number of fishermen focused on the mullet fishery and generating circa 9 M€ of annual income. The total amount of the sale of derivate products from the mullet (roe, carcass and guts) is between 15 and 24 M€. Mullet is the second most consumed fish in Mauritania and 95% of the landings in Mauritania are consumed within the sub-region (Mauritania, Senegal…).

Figure 3. Southern part of Spain Mugil landings by month including both lagoons and coastal zone for the period 2000-2004 (source Andalusia Autonomous Government).


2.3. South African fisheries

Mugilids are important resources for South Africa both for commercial and recreational fisheries. Current South African government policy aims to create more equitable access to marine resources and there is pressure to increase the inshore gill-net fishing effort. At present, the gill-net fishery in the Western Cape is confined to the cool temperate west coast. In order to ascertain the potential catch if the fishery was to expand along the warm temperate south-west coast, a program of experimental netting was conducted (Hutchings & Lamberth 2003). Estuarine and coastal marine sites were sampled bimonthly, using a range of commercial gill-nets (44-178 mm stretch-mesh). Although the target species, Liza richardsonii (Mugilidae), dominated the catches, at least 33 of the by-catch species, including Mugil cephalus, were also targeted by the commercial or recreational fishery sectors. The number of species captured and the by-catch per unit effort (CPUE) were greatest in areas currently closed to the commercial gill-net fishery. Multivariate analysis indicated significant differences in catch rates and composition between exploited west coast and unexploited south-west coast sites. A combination of natural biogeographical trends and the impact of over 100 years of commercial gill-netting on the west coast are the likely causes of these differences. A spatial expansion of the gill-net fishery could have a detrimental impact on overexploited line-fish stocks and lead to increased user conflict.

Interview questionnaires and access point surveys were used in order to describe and quantify the catch composition of the inshore net-fisheries in the Western Cape, South Africa (Hutchings & Lamberth 2003). A total of 138 562 fish, representing 29 species from 20 families, was recorded in 141 monitored commercial gillnet fishing operations between February 1998 and October 1999. Numerically, the legal target species, Liza richardsonii, dominated the catches, contributing 87% of the total gill net catch. L. richardsonii also numerically dominated the beach-seine hauls that were monitored (> 99%) with only four by-catch species being recorded in low numbers.

The largest fishery for Mugil cephalus in South African waters is found at Lake St Lucia where both legal and illicit gill net fisheries operate (Mann 1995). Although M. cephalus is not the primary targeted species, large numbers of these fish are captured by these operations since they are concentrated in North Lake and False Bay where adult M. cephalus are abundant.

2.4. Taiwanese fisheries

The grey mullet Mugil cephalus is an economically important species for both commercial fisheries and aquaculture in Taiwan. During winter, the adult mullet at ages of mainly 3-4 yr old migrates southward from the coastal waters of mainland China to the offshore waters of SW Taiwan to spawn, which contributes the important mullet roe industry in Taiwan. After hatching, their eggs and larvae disperse with the coastal current to the nursery area, and afterward the fishermen collect juveniles in the estuaries for restocking (Tung 1981, Chang & Tzeng 2000). According to the Taiwan fisheries statistics year book, the mean annual production of adult mullet was ca. 2000 tons and 1500 tons from capture fisheries and aquaculture, respectively during 1953~2005. Maybe due to

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Figure 4. Annual production of the capture fisheries and aquaculture of Mugil cephalus in Taiwan between 1953 and 2005.


overfishing and the pollution in the coastal area the production of the wild mullet dramatically decreased after 1980, and actually the annual production represents less than 10% of the highest level in 1980. In contrast, the production of mullet from aquaculture has increased thanks to the well-established aquaculture techniques resulting in a production that is approximately 2~4-fold greater than the production from capture fisheries in the recent 2~3 years (Fig. 4). In the other hand, the annual production of the juvenile mullet for restocking showed a periodic fluctuation at a 9 yrs interval between 0.7 and 22.9 in number of fish (×106) between 1967 and 2004 (Fig. 5a). The spatial distribution of the juvenile in the coasts of Taiwan was uneven; most of them were harvested from northwest and southwest coasts (Fig. 5b).

2.5. Mexican fisheries

Mugilids are important fisheries resources for artisanal fishermen in both coasts of Mexico, Pacific Coast and Gulf of Mexico Coast. According to Carta Nacional Pesquera (SAGARPA 2006), catches from the Pacific coast had a decreasing tendency from 4000 tons in 1986 to 3500 tons in 2002. Main fishing gear used is gill net with stretch-mesh between 63 and 89 mm, the length is variable between 75 and 300 m, and the height varies between 5 and 8 m. Captures take place in estuarine and coastal waters. Current fishing effort is realized by about 800 artisanal boats. There are fishing effort regulations for the grey mullet, M. cephalus: for example fishing season is closed in the states of Baja California, Baja California Sur, Sonora, Sinaloa, Nayarit and Jalisco, between 1st December and 31th January; and between 1st November and 31th December for states of Colima, Michoacán, Guerrero, Oaxaca and Chiapas. This species is considered at a full level of exploitation.

Mugilid fisheries on the Gulf of Mexico are dominated in one side by catches of grey mullet M. cephalus in the state of Tamaulipas, North-Western coast of Gulf of Mexico. Captures decreased from 5600 tons in 1988 to 3000 tons in 2002 (with the higher value of 6400 tons in 1996, and the lower value of 2800 tons in 1988). On the other side, catches of white mullet, Mugil curema, are very important in Veracruz State. Captures increased from 2000 tons in 1988 to 6000 tons in 2002 (with the higher value of 7400 tons in 1997 and the lower value of 600 tons in 1991). Captures take place in estuarine and coastal waters. The main fishing gear used is gill-nets. Actually there are fishing effort regulations for both species: fishing is forbidden from December 1st to February 28th, for the Tamaulipas and North of Veracruz states. Minimal catch size is 31 cm total length (TL) for the grey mullet and 26 cm TL for the white mullet. For both stocks the exploitation is considered at a full level of exploitation.

Figure 5. (a) Annual catches of juvenile Mugil cephalus in Taiwan during the fishing season (November to March) between 1967 and 2004. (b) Mean annual catches of juvenile M. cephalus in the 14 coastal districts in Taiwan (n° 1-14 of the insect diagram) from 1967 to 2005.

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3. Population genetics studies 3.1. The Mugilidae family phylo-genetics

An overview of the phylogenetic relationships within the entire family Mugilidae has to be undertaken. All past and present phylogenetic studies have dealt with mugilid species living sympatrically on a local or regional scale (Autem & Bonhomme 1980, Menezes et al. 1992, Lee et al. 1995, Caldara et al. 1996, Rossi et al. 1998a, Papasotiropoulos et al. 2001, Murgia et al. 2002, Papasotiropoulos et al. 2002, Rossi et al. 2004, Turan et al. 2005, Liu et al. 2007). With the exception of a mugilid phylogeny from India (Menezes et al. 1992) and from Taiwan (Lee et al. 1995), all phylogenetic studies have dealt with Mediterranean species (Fig. 6).

Due to a restricted species sampling (usually one species per genus), these studies are of limited interest for a global understanding of mugilid phylogenetic relationships. However, the research has highlighted the poor phylogenetic utility of meristic and morphometric characters usually used in the taxonomy and systematics of the Mugilidae. Another interesting finding when all data are compiled is the conflicting phylogenetic picture provided by the different studies (Fig. 6). For instance, Chelon labrosus is included in some studies as belonging to the Liza genus, suggesting polyphyly of the Liza genus, while in other studies this species is placed outside the Liza clade and in agreement with the current systematic classification.

In contrast, all studies have indicated Mugil cephalus as being the most divergent lineage within the family Mugilidae. Most of these studies relied on allozymic variability (Autem & Bonhomme 1980, Menezes et al. 1992, Lee et al. 1995, Rossi et al. 1998a, Papasotiropoulos et al. 2001, Turan et al. 2005) but more recently the mtDNA sequence was also used (Caldara et al. 1996, Murgia et al. 2002, Rossi et al. 2004). Caldara et al. (1996) using the sequence polymorphisms of the cytochrome b and 12S rRNA site suggested an apparent heterogeneous evolution rate among genera of the family Mugilidae. According to these authors, the mitochondrial genome of the Mugil genus would present an evolution rate faster than the rate observed in other mugilid genera. However, this preliminary observation has been conducted with only a small gene's portions (296 and 263 bp, respectively) and limited species samples (7 mugilids).

3.2. Population structure and population genetic diversity

Mugil cephalus is the most widespread species among the Mugilidae. Its distribution range, widely discontinuous, encompasses most of the coastal and estuarine environments in tropical and subtropical regions of the world. It is also observed in temperate regions such as the Mediterranean zone. This very unusual distribution range for an estuarine species, with limited dispersion abilities,

Figure 6. Phylogenetic relationships among Mediterranean species of the Mugilidae based on (A) allozymes (A1: Papasotiropoulos et al. 2001, A2: Turan et al. 2005) and (B) sequence polymorphism of an mtDNA gene (B1: Rossi et al. 2004, B2: Caldara et al. 1996).


has given rise to questions regarding its systematic status. Initial studies have tried to estimate broad genetic differences between remote populations. Using mtDNA, as well as allozymic loci, Crosetti et al. (1993, 1994), Rossi et al. (1998b) and Rocha-Olivares et al. (2000) have shown that populations from different oceans were highly isolated and estimates of gene flow rates extremely low (Nm= 0.03 to 0.05), which is in agreement with phylogeographic expectations considering the distribution range and dispersion ability of this species. These studies imply that even if there is an apparent absence of morphological differentiation on a global scale this does not imply absence of genetic structure. Using the sequence polymorphism of a hypervariable mtDNA region (the control region), Rocha-Olivares et al. (2000) indicated that Mugil cephalus populations presented high genetic diversity and extreme population divergence that questioned the taxonomic status of this species. However, as indicated by Caldara et al. (1996), the mtDNA mutation rate of the Mugil lineage is subject to an acceleration that prevents any comparison of the genetic divergence observed within M. cephalus populations to known intraspecific divergence. Nevertheless, using a different molecular class of markers (allozymic and mtDNA sequence polymorphism) populations identified as Mugil cephalus are all grouped together in a unique clade (Fig. 7) which would be consistent with the current taxonomy. However, there is still an ambiguity about the number of species included in this taxonomic unit, i.e. is there only one species as suggested by taxonomists using morphometric and meristic parameters or a set of sister species? This question is still unresolved.

On a more limited geographic scale, i.e. the regional approach (intra ocean / sea), few studies are currently available. Investigations conducted in the Gulf of Mexico using allozymic loci (Campton & Mahmoudi 1991) did not report any genetic heterogeneity, thus suggesting a high gene flow at a regional scale consistent with suspected dispersion abilities (especially during larval stage). In addition, no genetic structure was observed among Mediterranean samples (Crosetti et al. 1994, Rossi et al. 1998b). However, samples sizes were small limiting the power of statistical inferences concerning genetic differentiation.

On a local scale, to our knowledge, only one study has been conducted. This study concerned two

previously described sympatric populations of Mugil cephalus in Taiwan waters (Huang et al. 2001). The authors described, using only one allozymic locus (GPI-A), the genetic differentiation among a resident and migrant populations living in partial sympatry. Extensive differentiation exists at this locus and is probably the result of selective processes. This is a very preliminary investigation but results raise interesting questions because it has strong implications regarding our understanding about local adaptation and gene flow, topics that have been hardly debated.

Figure 7. Phylogenetic relationships among Mugil cephalus populations as determined by (A) allozymes (Rossi et al. 1998b) and (B) the mitochondrial genome (Crosetti et al. 1994).


As a summary, phylogenetic and population genetic investigations are needed to understand the

origin and biology of Mugil cephalus. This key species, at phylogenetic and ecological levels, while teasing scientists, has never been properly analysed. Active research into this missing information is now required. In order to develop original data to increase our knowledge around this question, different approaches are anticipated:

1. The intra-family phylogenetic relationships may be investigated using a set of representative species and genera of the Mugilidae. The mtDNA and nuclear gene sequence polymorphism would provide an interesting insight within the Mugilidae phylogeny. Specific attention to the Mugil genus may be guided by results of Caldara et al. (1996) which suggested a specific evolution rate within this lineage. This phylogeny would also include M. cephalus sampled in the different areas where the MUGIL consortium teams are present.

2. Inferences about the evolutionary process that shaped the genetic diversity and structure within Mugil cephalus require a phylogeographic approach. This approach has to be conducted at two different scales: a world and a regional scale. Previous investigations only compared genetic differentiation among samples from remote areas. Should extensive differentiation be found, it will not necessarily allow us to provide any evolutionary perspective regarding mechanisms influencing mugilid structure and genetic diversity. It is therefore important to identify the detailed phylogeographic structure (location of genetic discontinuities as well as the area of genetic homogeneity) to infer geological events or physical barriers that impacted past gene flow within this group. With those data it is possible to estimate a divergence time among different populations around the world.

3. Population genetic studies are already available at regional and fine scales using microsatellite markers (Miggiano et al. 2005) and would provide an estimation of the dispersive ability of this species. This approach would also allow delineating contemporary barriers to gene flow, which is important to understanding life history traits and the interpretation of variation in terms of plasticity or adaptive features.

4. Life history trait studies Few studies have been carried out on the life history traits of Mugil cephalus on a global scale

(Whitfield 1990). However, in America (e.g. Ibanez-Aguirre & Gallardo-Cabello 1996b, Ibanez-Aguirre et al. 1999, Nordlie 2000, McDonough et al. 2003, McDonough & Wenner 2003), Asia (e.g. Tung 1981, Chang et al. 2000), Oceania (e.g. Smith & Deguara 2003), Europe (e.g. Charalabous 1988, Cardona 2000) and to a lesser extent North Africa (e.g. Hamza 1999), the data generated by this type of studies can be used for fishery management purposes. Very few studies on mugilid life history traits have been published in Africa although extensive grey literature is available (e.g. Bok 1983). In contrast, numerous published studies have been undertaken on the growth and reproductive performances of the grey mullet in aquaculture (e.g. Silva & Perera 1976, Pillai et al. 1980, Oren 1981, Carr & Aldrich 1982, Kraul 1983, Tamaru et al. 1994, Jana et al. 2004). Nevertheless, although the widespread distribution of the species, common methods (i.e. for growth and/or reproduction studies) have not been used throughout the world and therefore make comparisons difficult on an international scale.

4.1. Age estimation and growth

A universal and validated method for age estimation of Mugil cephalus does not exist in the literature. Fish scales were originally used for mullet age estimation from the 1950s and have been used through to the 1970s (Tung 1959, VanderKooy & Guindon-Tisdel 2003). Since that time both scales (Tung 1981, Hamza 1999) and otoliths (Smith & Deguara 2003) have been used to estimate the age and growth on an annual basis using seasonal macro-increments. Ibanez-Aguirre & Gallardo-


Cabello (1996a) compared scales and otoliths for age estimation purposes and reported that fish scales could be used for juveniles, but otoliths provided better resolution for the older age classes. Interestingly Van der Kooy & Guindon-Tisdel (2003) tried to standardized otolith preparation methods for the age estimation of several species of the Gulf of Mexico, including M. cephalus, and recommended using a transverse section of the sagittal otolith (Fig. 8). Their work corroborated that of Smith & Deguara (2003) who, in the same year, also used transverse otolith sections. This preparation technique could now be used as a standard for interpreting the otolith macroincrements.

Despite widespread commercial and social significance, there is limited published information that validates ageing techniques to

assist with age-based stock assessments of M. cephalus fisheries (Smith & Deguara 2003). Validation has been accomplished on otoliths in at least one study (Smith & Deguara 2003). Otolith microincrements (Fig. 9), which are particularly important in daily ageing of fish larvae, have only been used for studies on the juvenile stages and recruitment in two geographic areas (Chang et al. 2000, Marin et al. 2003, Chang et al. 2006).

Finally growth data on M. cephalus are scarce in the classical literature but seem to be more available in the grey literature (although this kind of literature is less accessible). Even in studies focused on age validation, such as that of Smith & Deguara (2003), growth rate data and variability or modelling are not given. Nevertheless, the few studies involving growth evaluation have highlighted very variable growth rates depending on the environment (Ibanez-Aguirre et al. 1999). These variations had also been confirmed in aquaculture experiments (Oren 1981). In contrast, the growth rates of Taiwanese mullets were similar between populations with different behaviours, including those migrating offshore or those migrating to freshwater habitats (Chang et al. 2004a). Again, no comparison in growth of different populations has been undertaken on a global scale.

Figure 8. Sagittal otolith of Mugil cephalus viewed on the internal face under reflected light (above, scale bar = 1.5 mm) and transverse section of the otolith (bellow) under reflected light of a 5 yr old individual (black arrows indicate interpreted annuli) (VanderKooy & Guindon-Tisdel 2003).

Figure 9. Daily growth increments in polished otolith of juvenile Mugil cephalus photographed with a transmitted light microscope (a, b) and SEM (c). Otoliths in (b) and (c) were etched with EDTA; circle, discontinuous zones; P, primordium; scale bars, 50 μm for (a) and (b), 15 μm for (c) (Chang et al. 2000).


4.2. Reproduction

Migratory behaviour of M. cephalus generally occurs during the breeding season in different parts of the world (see after), with spawning migrations corresponding to movements of mature adults from their natural feeding areas, generally estuaries, to the open sea (Ibanez & Gutiérrez-Benítez 2004). In this species, the spawning grounds are located at sea, even though adults can spend almost their entire life in estuaries and/or lagoons (Cardona 2000). In Taiwan for example, the mullet spawning stock consists mainly of individuals migrating between the estuary and offshore marine zone (Chang et al. 2004a).

Interestingly, there are only a few published studies on the reproductive behaviour, or on the reproductive traits, for M. cephalus in different parts of the world: results have mainly been published from the Gulf of Mexico (Ibanez & Gutiérrez-Benítez 2004, Ibanez-Aguirre & Gallardo-Cabello 2004), the Mediterranean area (Cardona 2000), and in Taiwan (Chen & Su 1986). The maturation of gonads in relation to fish size seems to correlate well between the published data on reproduction traits for this species around the world.

The reproductive behaviour of M. cephalus is seasonal (see below), often occurring after wet seasons, and also reflected by the seasonal catches of fishermen in the Gulf of Mexico (Ibanez & Gutiérrez-Benítez 2004). Similar observations on spawning behaviour have been made on the west coasts of Africa (Bernardon & Vall 2004). More integrative studies on the reproductive cycles of M. cephalus throughout the world could highlight the relationship between the reproductive season and environmental physico-chemical parameters, as recorded in Mexico (Ibanez & Gutiérrez-Benítez 2004). Similarly, studies need to be undertaken on the possible effects of the environment on reproductive traits such as fecundity, size at first maturation, oocyte size, etc. which could give information on the conditions endured by individuals through their life.

5. Migration in the life history cycle Mugil cephalus is a diadromous fish species that migrates between continental and open seawater

environments during its life cycle (see above): juvenile and sub-adult stages grow in continental freshwater and brackish waters (estuaries and lagoons). Adults carry out off shore migrations to the sea for spawning, usually in the form of large schools that swim against prevailing currents (Smith & Deguara 2002).

The migratory history of M. cephalus covers the succession of the different saline environments (freshwater streams, estuaries or lagoons and seawater) occupied by fish along the different growth stages as proposed in the Figure 10. For example in the Taiwanese populations, the otolith microstructure, increment width and Sr:Ca (strontium/calcium) ratios show that the otolith section of juvenile M. cephalus can be divided into marine larval, estuarine pre-juvenile (J0), intermediate-juvenile (J1) and post-juvenile (J2) stages. Relative abundance, total length, otolith radius and daily age of the J0 stage displayed a geographic cline that increased from the central-western to northern and southern estuaries

Figure 10. Migration triangle in diffuse environment proposed by Secor (1999).


of Taiwan. This suggested that the tidal residual in the Taiwan Strait played an important role in estuarine recruitment dynamic of grey mullets in the western coast of Taiwan (Chang et al. 2000, Chang et al. 2006).

5.1. Eggs and larvae – Marine environment

Eggs are externally fertilised at sea and both eggs and larvae are pelagic within the marine environment. Although eggs are positively buoyant, they become negatively buoyant after fertilisation. Hatching takes around 48h after which larvae sink for the next 10 days. Thereafter, larvae exhibit positive phototaxis, actively swimming towards the surface. Larvae are then found near the surface between the coast and the continental slope over the shelf. Yet, the presence of larval M. cephalus has been reported to be evenly distributed across depths between 10 and 900 m off the South-eastern part of the US (Collins & Stender 1989). Larvae do not seem to carry diel vertical migrations, yet some may have changes in the rate of activity (Collins & Stender 1989). M. cephalus were often caught at night at the surface whereas one other species, M. curema, was caught during the day (Collins & Stender 1989) off the South-eastern USA. Feeding activity of M. cephalus has also been shown to be higher at dusk in the mouth of the Arno River (Torricelli et al. 1981) compared to other mugilids, more active during the day.

At this stage larvae already gather in schools. In fact, the species exhibits strong schooling tendencies from larval to adult stages (Fitzsimmons & Warburton 1992). In the form of schools, post-larvae then migrate towards estuaries recruiting at varying lengths depending on the geographical area. Recruiting fry have been observed swimming into estuaries in an “almost unbroken stream a few feet wide in shallow water along the shore” (Thomson 1955, in Smith & Deguara 2002). Pérez-Rufaza et al. (2004) indicate that although the settlement out of the plankton in mugilids occurs before entering estuaries and lagoons, still a few mugilid larvae in preflexion and flexion stages were caught in plankton samples in the Mar Menor lagoon (Eastern Spain).

Recruitment into estuaries may take between 4-6 months. This tends to occur earlier in higher latitudes. The timing of recruitment into estuaries and lagoons is supposed to be geared towards matching the most favourable conditions in the nursery area (Silva & De Silva 1981). As such, immigration to the lagoon expresses a trophic migratory behaviour (Pérez-Rufaza et al. 2004). These authors showed for a large Mediterranean lagoon that the peak in fish larval density matched the conspicuous annual peak in chlorophyll a. This peak in the density of fish larvae was not correlated in any way to water temperature, salinity or suspended solids.

Inshore migration of larvae is facilitated by dominant oceanographic conditions at large since larvae drift with currents (Chang et al. 2000, Chang et al. 2006) but see Ibáñez & Gutiérrez-Benítez (2004).

5.2. Recruits – Estuaries, lagoons and continental freshwater environments

Young recruits colonise the lower part of estuaries and may progressively extend their distribution within continental waters to the upper parts of the watersheds. This colonisation of the watershed depends primarily on the osmotic regulation capabilities of M. cephalus larvae (Nordlie et al. 1982). In experimental conditions, M. cephalus of 20-39 mm in size survived the immediate transfer from seawater to all salinities except freshwater (Nordlie et al. 1982, Walsh et al. 1991).

This colonisation of the upper freshwater streams of the watershed may push juvenile fish to actively overcome physical barriers such as dams in their upriver migration (Kowarsky & Ross 1981, Russell 1991).

It has been shown that juvenile fish actively avoid polyhaline and euhaline waters preferring freshwater and oligohaline waters in a stratified study carried out in several inland estuaries of the island of Menorca (Balearic Islands, Western Mediterranean) (Cardona 2000). Immature fish occupy waters with similar saline profiles, yet they also avoid the freshwater environment in winter and


spring. Instead, adult fish avoid freshwater concentrating in polyhaline sites during summer and autumn and thereafter moving to euhaline areas in winter and spring (Cardona 2000), probably as part of their off-shore migration associated to spawning. A stay in freshwater is not obligatory for newly recruited M. cephalus. Evidence has been provided of estuarine preference for schools of estuarine juveniles which never entered freshwater (Thomson 1955, 1959, Leber et al. 1995). In Australia, recruits with sizes smaller than 50 mm are primarily found in intertidal areas (Chubb et al. 1981). The mechanisms of colonisation and habitat selection of M. cephalus within continental waters are thus poorly understood.

The analysis of otoliths Sr:Ca ratios as tracers of water salinity has greatly contributed to study the history of salinity preferences of M. cephalus. Early studies also showed that the use of otolith oxygen isotopes to trace M. cephalus migrations across different salinities could also be highly appropriate and should be explored further (Meyer-Rochow et al. 1992). According to the temporal change of otolith Sr:Ca ratios by electron probe microanalyzer (EPMA), the migratory environmental history of the adult mullet beyond juvenile stage can be classified into two types (Fig. 11): Type 1, mullets with otolith Sr:Ca ratios between 4.0 - 13.9×10-3 may indicate that they migrate between estuary and offshore but rarely enter the freshwater habitat; Type 2, otolith Sr:Ca ratios decreased to a minimum value of 0.4×10-3 which indicate that they migrate to freshwater habitat. The mullets beyond juvenile stage usually left estuary to offshore, but a few mullets with ages less than 2 years old may move to freshwater habitat. Mullets collected from nearshore and offshore consisted mainly of Type 1, while those collected from the estuaries were mixed of both Types 1 and 2. The mullet spawning stock consisted mainly of Type 1 fish. The growth rates of the mullet were similar between Types 1 and 2. Therefore, the migratory patterns of the mullet are more complicated than previously thought in Taiwan (Chang et al. 2004a, Chang et al. 2004b) and are not clearly known in the rest of the world.

After recruiting to an estuary or lagoon, M. cephalus seems to remain in the same watershed until reaching maturity. Tagging programs of M. cephalus in freshwater streams have shown that fish tagged in South Australia did not show mean monthly travelled distances higher than 20 km (and actually closer to 5 km) (Gehrke et al. 2001). Downstream movements were followed by upstream returns to the site of tagging evidencing a narrow home range for adult stripped mullet (Gehrke et al. 2001). The fact is that the species is not a strong swimmer (Mitchell 1989). Nonetheless, some may migrate between different estuaries or catchments as shown by other tagging studies (Thomson 1955). Occasionally, juveniles and adults are flushed away from their nursery estuaries in what seems to be a forced export of estuarine residents caused by exceptional heavy rains. These mature and immature fish which may eventually migrate between estuaries do not feed and have undeveloped gonads.

In an attempt to study the fidelity to nursery areas of M. cephalus, the otolith trace elemental composition was used as an indicator to discriminate the juvenile origin among estuaries of Taiwan. Out of twelve elemental concentrations (Li, Na, Mg, K, Mn, Fe, Ni, Cu, Zn, Sr, Ba, and Pb) to calcium molar ratios in otoliths of the juvenile mullet analyzed by inductively coupled plasma-mass

0

5

10

15

0 1000 2000 3000 4000 5000 6000

Type 1

0

5

10

15

0 1000 2000 3000 4000 5000 6000

Type 2

Sr:C

a ra

tio (×

10-3

)

Distance from primordium to otolith edge (μm) Figure 11. Temporal changes in the Sr:Ca ratios in the otoliths of Type 1 (a) and Type 2 (b) adult grey mullet. Solid triangles, estuarine check; open triangles, annuli. The grey bands between the Sr:Ca ratios 3-7×10-3 indicate mullet migration in brackish waters (modified from Chang et al. 2004a).


spectrometry (ICP-MS), five elements (Mn, Ni, Zn, Sr, and Ba) were found to be significantly different for the fish among estuaries. The canonical discriminant function also indicated that 10 of 12 elemental ratios (except Li:Ca and Cu:Ca) played significant role on the discrimination of the juvenile mullet among estuaries. Among them, Mn:Ca, Ni:Ca and Zn:Ca contributed approximately 49.8 % in the first canonical function of the discrimination, while Ba:Ca and Sr:Ca contributed 32.9 % in the second function. As a result, 84 % of the mullet larvae could be assigned to their recruited estuaries with their otolith chemical signatures, indicating that elemental composition in otolith of the fish can be used as a natural tag to trace their nursery areas (Wang et al. 2006).

5.3. Adults – Marine environment

Adults congregate in the lower part of the estuary in their pre-spawning migration to the sea. Migrating fish vary in age and size depending on the population (Table 1).

Table 1. Size and age of first maturity in different populations of Mugil cephalus (Ameur et al. 2003). See cited references in Ameur et al. (2003). FL, fork length; SL, standard length; TL, total length.

Areas Size at 1st maturity (cm) Age at 1st maturity (yr) Reference

Atlantic America ♂ 23 - 24 / ♀ 24 - 31 3 Broadhead (1953) (Florida) Atlantic America 23 - 27 - Greely et al. (1987) (Florida) Atlantic Africa 28 - 35 (FL) 3 - 4 Landret (1974) (Senegal) Atlantic Africa ♂ 28 / ♀ 27 (SL) 3 Brulhet (1975) (Mauritania) Mediterranean ♂ 28 / ♀ 27 (SL) 2 Farrugio (1975) (Tunisia) Mediterranean 38 - 40 (TL) - Brusle & Brusle (1977) (Tunisia) Mediterranean ♂ 36 - 37 / ♀ 40 - 41 - Brusle (1981) (Tunisia) Mediterranean 47 (TL) 5 Demiczi (1958) (Turkey) Mediterranean ♂ 40 / ♀ 41 (FL) 5 Erman (1959) (Turkey) Atlantic Africa ♀ 37 (FL) 5 Ameur et al. (2003) (Morocco)

Although seawater salinities are not required for the full maturation of the gonads, the success of fertilisation depends on osmolarity (Lee et al. 1992) and adults migrate to open seawater for spawning. Other factors such as water temperature and photoperiod may also be determinant in the vitellogenesis (Kuo et al. 1974) resulting in different periods of reproduction across the range of distribution of the species (Table 2).


Table 2. Timing of reproduction of Mugil cephalus from different populations (Ameur et al. 2003). See cited references in Ameur et al. (2003).

Area Reproduction period during the year References

J J A S O N D J F M A M Turkey Erman (1959) Caspian Sea Avanesov (1972) Atlantic (Morocco) Ameur et al. (2003) Mediterranean (Egypt) Faouzi (1938) Adriatic Sea Morovic (1963) Mediterranean (Tunisia) Brusle & Brusle (1977) Mediterranean (Tunisia) Brusle (1981) Mediterranean (Tunisia) Farrugio (1975) Gulf of Mexico Ibañez (1994) Atlantic (Senegal) Landret (1974) Atlantic (USA) Greely et al. (1987)

It has to be noted that the downstream migration of sub adults in their outward migration to the sea can be disrupted by physical barriers such as weirs even provided with sluice gates (Russell 1991).

Once out at sea, adults migrate against local or regional dominant currents (e.g. in East and West

Australian coasts). The extent of this migration varies between geographical areas: migrations of over 700 km have been reported in Australia whereas in the coast of Florida (USA) 90% of tagged fish were recaptured within 20 miles from the site of release. The longest migration reported was 150 miles (Idyll & Sutton 1952). Similar results were reported for M. cephalus in North Carolina (Bacheler et al. 2005). Not all fish follow the same migratory route. While northward migrations are dominant in Australia and southward migrations are dominant in North Carolina, a non negligible part of the population were recaptured in opposite locations to the mainstream of migration in both study areas.

6. Bio-indicator studies The aquatic environment is particularly vulnerable to the toxic effects of chemicals that might

affect the biotransformation and detoxification enzymes of aquatic organisms, either as inhibitors or as modulators of enzyme activity. These contaminants are usually present as very complex mixtures, and exhaustive chemical analysis is difficult and would not give information on their potential effect and/or synergy on aquatic organisms. The use of biomarkers can offer an integrated evaluation of the effects of pollutants in wildlife. Mugil cephalus is a species that feeds mainly on benthic organisms and detritus, and possesses several characteristics required in an indicator species, such as extreme salinity tolerance, and presence in a variety of habitats. It is an economically important protein source for humans and is used locally as a bio-indicator of organic pollution.

Few biomarker studies have been performed using Mugilidae. Ferreira et al. (2005) showed that in the grey mullet the presence of pollutants induced oxidative stress responses. The decrease in antioxidant enzyme activities observed in captive mugilids confirms that these species are being exposed to oxidative stress due to environmental pollutants and that cell response can change when transferred to an unpolluted environment. Another study examining GST and CYP1A-dependent EROD activities in mullet liver showed that ionic detergents strongly inhibited EROD activity, whereas considerably less inhibition was observed with GST catalyzed activities (Sen & Semiz 2006). However, in PAH environmentally contaminated sites, ionic detergents must also be considered.

The use of several biomarkers for an assessment on the effect of dredged material on mullet was studied by Regoli et al. (2002). Bioavailability of specific classes of pollutants was evaluated by analyzing levels of metallothioneins, the activity of cytochrome P450 1A (CYP1A) and of glutathione


S-transferases. The balance between pro-oxidant challenge and antioxidant defences were studied, and the appearance of damage caused by oxidative stress was evaluated. Results showed that antioxidants were useful in revealing early warning “biological responses”, while integration with total oxyradical scavenging capacity analyses indicated whether such changes also reflected a more integrated and functional “biological effect”, with possible consequences at the organism's level.

Overall, previous studies have shown the feasibility of biomarker use on mullet and the usefulness of these tools for monitoring potential effects on a representative group of fishes such as mugilids. These biomarkers could be studied in the framework of this project and spatial and temporal variations could also be addressed.

7. Conclusions The species Mugil cephalus clearly represents a good candidate as an indicator species in order to

follow littoral environmental changes, due to its cosmopolitan distribution in a wide variety of habitats throughout the world. A global observation network coordinating the use of this species as an indicator of the state of coastal areas, by observing the population genetics, the life history trait variations and the physiological responses to salinity or pollution, could be particularly relevant. Initially, further phylogenetic and population genetic investigations are needed to understand the origin, distribution and biology of M. cephalus around the world. Secondly, collating the different adaptive responses in term of growth and reproduction (e.g. fecundity, size at first maturation, oocyte size) for different populations could constitute the basis for the characterization of the environmental pressures. The different methods used for life history trait calculation should be standardized at a higher scale. Finally, the development of (new) biomarkers to identify potential responses of the populations should be an ultimate goal of this investigation.

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9. Author addresses

J. Panfili

Postal: IRD - UR 070, UMR 5119, Laboratoire ECOLAG, Université Montpellier 2, cc 093, Place E. Bataillon, 34095 Montpellier Cedex 5, France Email [email protected]

C. Aliaume

Postal: UMR 5119, Laboratoire ECOLAG. Université Montpellier 2, cc 093, Place E. Bataillon. 34095 Montpellier Cedex 5, France Email [email protected]

P. Berrebi

Postal: Institut des Sciences de l'Evolution, UMR5554, Université Montpellier 2, cc 065, Place E. Bataillon, 34095 Montpellier Cedex 5, France Email [email protected]

C. Casellas

Postal: UMR-5569 Hydrosciences, IUP - Faculté de Pharmacie, 15 Av. Charles Flahault, B.P. 14 491, 34093 Montpellier Cedex 3, France Email [email protected]

C.W. Chang

Postal: National Museum of Marine Biology and Aquarium, No. 2, Houwan Road, Checheng, Pingtung, 94450 Taiwan, Republic of China Email [email protected]

P.S. Diouf

Postal: WWF - WAMER, 9639 Sacré Coeur III, B.P. 22928, Dakar, Senegal Email [email protected]

J.D. Durand

Postal: IRD - UR 070, UMR 5554 ISEM, Station Méditerranéenne de l’Environnement Littoral, quai de la Daurade, 34200 Sète, France Email [email protected]

D. Flores Hernández

Postal: Centro EPOMEX, Universidad Autónoma de Campeche, Av. Agustín Melgar y Juan de la Barrera, Campeche, Cam. CP. 24030, Mexico Email [email protected]

F. García de León

Postal: CIBNOR S.C., Mar Bermejo No. 195, Col. Playa Palo de Santa Rita, PO Box 128, 23090 La Paz, B.C.S., Mexico Email [email protected]

P. Lalèyè

Postal: Faculté des Sciences Agronomiques de l’Université d’Abomey-Calavi, 01 BP 526, Cotonou, Benin Email [email protected]

B. Morales-Nin

Postal: Instituto Mediterráneo Estudios Avanzados (CSIC/UIB), Miguel Marqués 21, 07190 Esporles, Islas Baleares, Spain Email [email protected]

J. Tomás

Postal: Calle Campoamor 6 -4izda, Madrid 28004, Spain Email [email protected]

W.N. Tzeng

Postal: Institute of Fisheries Science, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei, 10617 Taiwan, Republic of China Email [email protected]

V. Vassilopoulou

Postal: Institute of Marine Biological Resources, Hellenic Centre for Marine Research, Agios Kosmas, Hellenikon, 16777, Athens, Greece Email [email protected]

C.H. Wang

Postal: Institute of Biodiversity, National Chengkung University, No. 1, Tahsueh Road, Tainan, 70101 Taiwan, Republic of China Email [email protected]

A.K. Whitfield

Postal: SAIAB, Private Bag 1015, Grahamstown 6140, South Africa Email [email protected]

INCO-CT-2006-026180 MUGIL Deliverable 1 - January 2007

10. Annex

SEMINAR 1

MUGIL Main Uses of the Grey mullet as Indicator of

Littoral environmental changes 2006 - 2009

Agenda 02 - 04 November 2006


LOGO to be

done

SEMINAR 1

MUGIL

Main Uses of the Grey mullet as Indicator of Littoral environmental changes

2006 - 2009

02 - 04 November 2006

Homepage: Link soon Coordinator: J. Panfili (IRD)

Objectives This kick-off meeting will serve the purpose of introducing the different teams involved in MUGIL and will be the starting point on discussions for the DB construction and the construction of the internet web pages

European commission

INCO-CT-2006-026180

MUGIL

Contents

Page

1. OBJECTIVES OF MUGIL S1......................................................................................................................... 2

2. AGENDA ........................................................................................................................................................... 2

3. LIST OF PARTICIPANTS .............................................................................................................................. 5


1. Objectives of MUGIL S1 Dear MUGIL colleagues, The MUGIL kick-off meeting (Seminar 1) will be held in Dakar (Senegal), 2-4 November 2006, at the IRD Hann research institute. This meeting will be a plenary session with all MUGIL participants. This kick-off meeting will serve the purpose of introducing the different teams involved in MUGIL, with presentations and discussions around the current research carried on the species Mugil cephalus or on subjects related to MUGIL. Second it will be the basis of structuring the discussions around the thematic research areas covered by the project. It will also be the starting point on discussions for the DB construction and the construction of the internet web pages. The milestone will be a deliverable on the state of art on research on Mugilidae, and the possible use of M. cephalus as an indicator for estuarine environments. S1 will also allow to choose a Steering Committee among MUGIL participants. I am looking forward to seeing you soon in Dakar. Yours sincerely, Jacques Panfili 2. Agenda 2 November 2006

Presentation of each laboratory and specific fields of research linked with MUGIL 8h30 - 9h00: bus from hotel to IRD Hann

9h - 9h10 - Christian Colin (IRD Senegal representative) / Jacques PANFILI (IRD #1): Welcome

(10 min)

9h10 - 10h10 - Jacques PANFILI (IRD #1): IRD research institute (15 min) - RAP research unit and its

interest for Mugil research (30 min + 15 min)

10h10 - 10h40 - Jean-Dominique DURAND (IRD #1): State of the art of genetic studies in Mugil

cephalus (20 min + 10 min)

10h40 - 10h55 - Sébastien TRAPE (IRD #1): Mugil recruitment at a spatial and time scale in a West

African hypersaline estuary: PhD project (10 min + 5 min)

10h55 - 11h20 Coffey break


11h20 - 12h10 - Javier TOMÁS (associate researcher IRD #1): Otolith microchemistry: principles,

applications, tools and limits (40 min + 10 min)

12h10 - 12h50 - Catherine ALIAUME (UM2 #4): ECOLAG Laboratory presentation and specific topics

linked to MUGIL (30 min + 10 min)

12h50 - 14h00 LUNCH at IRD Hann (La Paillote)

14h00 - 14h40 - Patrick BERREBI & coll. (CNRS #4): Introns molecular markers for species

determination of Moroccan and French grey mullets, including Mugil cephalus (30 min + 10 min)

14h40 - 15h40 - Claude CASELLAS (UM1 #4): Fish biomarkers as a tool for monitring anthropogenic

stress. Presentation of two research teams: UMR "Hydrosciences" and INERIS "ecological risk assessment" (45 min + 15 min)

15h40 - 16h10 - Papa Samba DIOUF (WWF-WARMER #5): WWF in West Africa (20 min + 10 min)


16h30 - 17h30: bus from IRD Hann to hotel

DINER free

3 November 2006 Presentation of each laboratory and specific fields of research linked with MUGIL (continue) 8h00 - 8h30: bus from hotel to IRD Hann

8h30 - 9h10 - Francisco Javier GARCÍA DE LEÓN (CIBNOR #8): Microsatellite markers can tell us

something about genetic divergence on populations of Mugil sp in world scale and something more? / CIBNOR infrastructure for next Genetic workshop at La Paz, BCS Mexico (30 min + 10 min)

9h10 - 9h40 - Ana L. IBAÑEZ (UAMI - CIBNOR #8): Recent experience in Mugil cephalus studies in

the Gulf of México (20 min + 10 min)

9h40 - 10h20 - Philippe LALEYE (FSA-UAC #9): Diversity and status of Mugilids in lagoons of Bénin

(West Africa) (30 min + 10 min)



10h40 - 11h40 - Beatriz MORALES NIN (IMEDEA UIB #10): What information can we extract from

Mugil otoliths? (45 min + 15 min)

11h40 - 13h10 - Wann-Nian TZENG, Chih-Wei CHANG & Chia-Hui WANG (IFS-NTU #12): Grey

mullet in Taiwan: fishery, life history and migratory environment (1h30 min)


14h00 - 15h00 - Vassiliki VASSILOPOULOU (HCMR #13): Presentation of the Hellenic Center for

Marine Research Institutes involved in MUGIL, focusing particularly on relevant research activities (45 min + 15 min)

15h00 - 16h15 - Alan WHITFIELD (SAIAB #14): Past and present mugilid research in South Africa (60

min + 15 min)


16h45 - 17h00 - Jacques PANFILI (IRD #1): MUGIL organisation, (pre)financing and overall timetable

(15 min)

17h00 - 18h00 - MUGIL internet website

18h00- 18h30: bus from IRD Hann to hotel

MUGIL DINER (with confirmation)

4 November 2006 8h30 - 9h00: bus from hotel to IRD Hann

9h00 - 12h30 - MUGIL internet website (continue) - MUGIL database - Conclusions of MUGIL S1


13h20- 13h50: bus from IRD Hann to hotel

16h00 - 18h00 - Visit of Soumbedioune fish market and traditional (artisanal) market DINER free


3. List of participants

Name Institute Country MUGIL N°

Date of Arrival

Date of Departure

Jacques PANFILI IRD France 1 01/11/2006 07/11/2006 Jean-Dominique DURAND IRD France 1 01/11/2006 05/11/2006 Sébastien TRAPE IRD France 1 02/11/2006 03/11/2006 Javier TOMAS assoc. res. Spain 1 30/10/2006 5/11/2006 Catherine ALIAUME UM2 France 4 01/11/2006 05/11/2006 Patrick BERREBI CNRS France 4 01/11/2006 04/11/2006 Papa Samba DIOUF WWF Senegal 5 02/11/2006 04/11/2006- Francisco GARCIA de LEON CIBNOR Mexico 8 31/10/2006 07/11/2006 Ana L. IBANEZ UAMI Mexico 8 30/10/2006 07/11/2006 Philippe LALEYE FSA-UAC Benin 9 01/11/2006 05/11/2006 Beatriz MORALES NIN IMEDEA Spain 10 01/11/2006 06/11/2006 Wan-Nian TZENG IFS-NTU Taiwan 12 01/11/2006 07/11/2006 Chih-Wei CHANG IFS-NTU Taiwan 12 01/11/2006 07/11/2006 Chia-Hui WANG IFS-NTU Taiwan 12 01/11/2006 07/11/2006 Vassiliki VASSILOPOULOU HCMR Greece 13 30/11/2006 06/11/2006 Alan WHITFIELD SAIAB S. Africa 14 01/11/2006 05/11/2006

Meeting venue IRD Centre de Hann - Route des Pères Maristes - B.P. 1386 - 18524 Dakar - Senegal. Tel: +221 849 35 35 Hotel venue HÔTEL DIARAMA Route de Ngor - B.P. 8092 - Dakar Yoff - Senegal Tel: +221 820 27 24 - Fax: +221 820 27 23 Internet: http://www.au-senegal.com/pages/diarama.php Prices (special rate for IRD): Single room (including breakfast) = 39 500 CFA / day (+ taxes 600 CFA/pers/d) Double room (including breakfast) = 44 000 CFA / day (+ taxes 600 CFA/pers/d)

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