Feeding habits of European hake (Merluccius merluccius) in the central Mediterranean Sea.European hake (Merluccius merluccius) is an important predator of deeper shelf-upper slope Mediterranean communities. It is a nectobenthic species distributed over a wide depth range (20-1000 m) throughout the Mediterranean Sea Mediterranean Sea [Lat.,=in the midst of lands], the world's largest inland sea, c.965,000 sq mi (2,499,350 sq km), surrounded by Europe, Asia, and Africa. Geography The Mediterranean is c.2,400 mi (3,900 km) long with a maximum width of c. and the north east Atlantic region (Fisher et al., 1987). Notwithstanding the ecological and economic importance (Oliver and Massuti, 1995) of hake in the Mediterranean, many aspects of its biology (e.g., recruitment and reproduction), due to multiple spawning (Sarano, 1986) and the current state of exploitation, are poorly understood (Arneri and Morales-Nin, 2000). Recent studies on hake feeding habits in the Mediterranean (Papacostantinou and Caragitsou, 1987; Bouaziz et al., 1990; Oliver and Massuti, 1995) have focused on 0-3 age groups using data from trawl trawl - To sift through large volumes of data (e.g. Usenet postings, FTP archives, or the Jargon File) looking for something of interest. catches (Recasens et al., 1998; Colloca et al., 2000). For this reason, trophic trophic /tro·phic/ (tro´fik) (trof´ik) pertaining to nutrition. troph·ic adj. Of, relating to, or characterized by nutrition. habits of older individuals (Bozzano et al., 1997) and possible ontogenesis-related diet changes are almost unknown. Therefore, in this study 2we combined samples from trawl and gillnet gill·net tr.v. gill·net·ted, gill·net·ting, gill·nets To catch (fish) by means of a gill net. fisheries collected in the same fishing ground (Colloca et al., 2000) to address these issues. Materials and methods The study area is located off the central western coasts of Italy, covering 13,404 [km.sup.2] between 20 and 700 meters depth (outer boundaries: latitude 40[degrees]52'64, longitude 13[degrees]23'13; latitude 42[degrees]20'30, longitude 11[degrees]16'32). Monthly size-stratified samples were obtained from spring 1997 to winter 1998 both from bottom-trawls, gillnet commercial-vessels, and from commercial landings. Trawlers catch mainly 0-2 year-old juveniles; they rarely capture adults (Aldebert et al., 1993; Abella et al., 1997; Ardizzone and Corsi, 1997). The gillnet fishery exploits mainly adults of the species (>25 cm TL). Caught fish were kept on ice, subsequently frozen to prevent digestion of their stomach contents, taken to the laboratory, measured (total length: TL) to the nearest 1 mm, and weighed to the nearest 0.01 g. Sex and maturity stage were also recorded. Maturity state was determined by macroscopic macroscopic /mac·ro·scop·ic/ (mak?ro-skop´ik) gross (2). mac·ro·scop·ic or mac·ro·scop·i·cal adj. 1. Large enough to be perceived or examined by the unaided eye. 2. analysis of the gonads by using the maturity scale for partial spawners (Holden and Raitt, 1974). Stomachs were removed and their contents weighed to the nearest 0.001 g. Prey items were identified and sorted into taxonomic groups to the species level whenever possible. When the state of digestion was more advanced, prey were checked and grouped into unidentified fish, cephalopods, or crustaceans. The degree of digestion of the prey was not considered in the analysis. Empty stomachs and those with partially everted or unidentified contents were excluded from the total sample. With the exception of the largest individuals (grouped into two heterogeneous length classes), all remaining hakes in the sample were grouped into 5-cm length classes. The study of size-related diet variations was based on these groups. The contribution of each food item to the diet of these fish length groups was evaluated by using the index of relative importance (IRI Iri (ē`rē`), former city, North Jeolla (Cholla) prov., SW South Korea. An agricultural center and transportation hub, it was absorbed into Iksan. , Pinkas et al., 1971) as modified by Hacunda (1981): IRI = F(N + W). This index, expressed as IRI% = IR[I.sup.- [summation]IRI] x 100, incorporates the percentage by number (N%), wet weight (W%), and frequency of occurrence (F%) (Hyslop, 1980). Hierarchical cluster analysis Cluster analysis A statistical technique that identifies clusters of stocks whose returns are highly correlated within each cluster and relatively uncorrelated across clusters. Cluster analysis has identified groupings such as growth, cyclical, stable, and energy stocks. and nonmetric multidimensional scaling (NMDS NMDS National Minimum Data Set NMDS Nursing Minimum Data Set NMDS Non-Metric Multidimensional Scaling NMDS Narrowband Multi-Service Delivery System NMDS New Music Distribution Service NMDS National Disaster Medical System NMDS Near Maximum-Distance Separable ), based on Bray-Curtis similarity and on the IRI%, were used for classification and ordination of hake size classes (Clarke and Warwick, 1994). Results A total of 2761 hakes between 5 and 90 cm TL were collected (Table 1). The total number of prey was about 1700, divided into 46 different species. Cluster and NMDS analysis (stress=0.02) based on the IRI allowed the identification of four groups below 50CA similarity that were separated along a size gradient (Fig. 1). [FIGURE 1 OMITTED] Euphausiids (Nictiphanes couchi, IRI=76%) and mysids (Lophogaster typicus, IRI=22%) dominated the diet of group A (hake between 5 and 10.9 cm TL), and decapods were the secondary prey. Group B (hake from 11 to 15.9 cm TL) showed a more heterogeneous diet characterized by a high occurrence of euphausiids but also with a considerable number of decapods (IRI=18%). Decapods were represented by a wide variety of species, such as Chlorotocus crassicortzis, Alpheus glaber, Plesionika heterocarpus, PasiptTaea sivado, and So/erzocera membranacea. Pisces and mysids showed lower percentages (IRI=15%, and 4%, respectively). Sepiolidae (IRI=0.9%), Sepietta oweniana and Alloteuthis media, dominated among cephalopods. The data suggest a gradual change towards a fully piscivorous piscivorous fisheating; said of birds. diet (Fig. 2) which begins around 16 cm TL and is completed when sexual maturity is attained (TL=32 cm for males and TL=38.5 cm for females; Colloca et al., 2002). [FIGURE 2 OMITTED] The importance of teleosts strongly increased in group C (hake from 16 to 35.9 cm TL), where they accounted for 91% of hake diet. The main prey were Clupeiformes (IRI=61 %), Sardina pilchardus Noun 1. Sardina pilchardus - small fishes found in great schools along coasts of Europe; smaller and rounder than herring pilchard, sardine clupeid, clupeid fish - any of numerous soft-finned schooling food fishes of shallow waters of northern seas and Engraulis encrasicolus. Fish (IRI=96%) represented almost the entire diet of group D (>36 cm TL). In this group a shift towards Centracanthidae (Spicara flexuosa, Centracanthus cirrus) and a simultaneous decline in consumption of Clupeiformes was observed. Among decapods (IRI=4%), two species occurred most frequently: Processa spp. and S. membranacea. Euphausiids, mysids, and cephalopods were absent in the diet of hakes larger than 36 cm TL. Cannibalism cannibalism (kăn`ĭbəlĭzəm) [Span. caníbal, referring to the Carib], eating of human flesh by other humans. of hake juveniles also accounted for some of the diet and increased with predator size. In hake between 36 and 40 cm TL cannibalism represented 12q of IRI, reaching the highest values (IRI=17%) among larger individuals (TL >51 cm). Discussion Hake is a top predator that occupies different trophic levels during its ontogenetic on·to·ge·net·ic adj. Of or relating to ontogeny. development. Hake size classes are differentiated along food niche dimensions according to according to prep. 1. As stated or indicated by; on the authority of: according to historians. 2. In keeping with: according to instructions. 3. different prey sizes or different prey taxa. Hake diet shifted from euphausiids, consumed by the smaller hakes (<16 cm TL), to fishes consumed by larger hakes. Before the transition to the complete icthyophagous phase, hake showed more generalized feeding habits where decapods, benthic ben·thos n. 1. The collection of organisms living on or in sea or lake bottoms. 2. The bottom of a sea or lake. [Greek. (Gobiidae, Callionymus spp., Arnoglossus spp.) and nectonic fish (S. pilchardus, E. encrasicolus) dominated the diet, and cephalopods had a lower incidence. Specific size-related differences in prey spectrum seem to be associated with different spatial distributions or genetic needs (or with both) (Flamigni, 1984; Jukic and Arneri, 1984; Velasco and Olaso, 1998). The patterns observed in the present study indicated a strong partitioning among hake size classes. Two main thresholds associated with ontogenesis-related diet changes have been identified. The first one was observed around 16 cm TL and corresponded to a significant change in depth distribution. The second, around 36 cm TL, corresponded to the attainment of sexual maturity (Colloca et al., 2002). Although hakes are demersal de·mer·sal adj. 1. Dwelling at or near the bottom of a body of water: a demersal fish. 2. fishes, they feed typically upon fast-moving pelagic pelagic living in the middle or near the surface of large bodies of water such as lakes or oceans. prey that are ambushed in the water column (Alheit and Pitcher, 1995). There is evidence that hakes feed in mid-water or near the surface at night, undertaking daily vertical migrations (Hickling, 1927; Papacostantinou and Caragitsou, 1987; Orsi-Relini et al., 1989) which are more frequent for juveniles. Small hakes feed daily on small Euphausiacea (Nictiphanes couchi). This school-forming planktonic plank·ton n. The collection of small or microscopic organisms, including algae and protozoans, that float or drift in great numbers in fresh or salt water, especially at or near the surface, and serve as food for fish and other larger organisms. crustacean crustacean (krŭstā`shən), primarily aquatic arthropod of the subphylum Crustacea. Most of the 44,000 crustacean species are marine, but there are many freshwater forms. carries out vertical migrations at night (Casanova, 1970; Franqueville, 1971; Vallet and Dauvin, 2001). They rise to near the surface at night to feed on phytoplankton phytoplankton Flora of freely floating, often minute organisms that drift with water currents. Like land vegetation, phytoplankton uses carbon dioxide, releases oxygen, and converts minerals to a form animals can use. and sink during daylight between 50 and 800 m depth (Buchholz et al., 1995). Juveniles of M. merluccius may follow such migrations, moving from near the bottom, 100-200 m depth, to midwater at night (Froglia 1973; Papaconstantinou and Caragitsou, 1987; Orsi-Relini et al., 1989). Nocturnal vertical migration behavior has been described for gadoids such as hake and cod and is considered responsible for the reduction of trawl catches of these fish at night (Beamish, 1966; Bowman and Bowman, 1980). Considerable diet changes have been observed after the first year of life (>16 cm TL) when juveniles move from nursery areas on the shelf-break and upper slope to the middle shelf (Andaloro et al., 1985; Ardizzone and Corsi, 1997). The data indicate that such migration is induced by a change in trophic requirements. In this size class, diet changed to fish prey (Clupeiformes), and the importance of the small epiplanktonic crustaceans (Euphausiacea) strongly decreased. Clupeiforms S. pilchardus and E. encrasicolus are distributed largely on the continental coastal shelf forming schools usually deeper than 25 m (Fisher et al., 1987). The size-depth distribution pattern of hake was confirmed by experimental trawl surveys carried out in the Mediterranean (Relini and Piccinetti, 1996; Relini et al., 1999). Juveniles (modal length of 10 cm TL) are found mostly between 100 and 200 m depth. Intermediate hakes reach the highest abundance mainly on the shelf (<100 m). Large hakes (>36 cm) are found in a wide depth range but concentrate on the shelf break during the spawning period (Recasens et al., 1998; Colloca et al., 2000; Alvarez et al., 2001). Growth induces a continuous qualitative and quantitative change in diet that is reflected in the increasing mean weight of prey and decreasing mean number of prey items per stomach. The shift towards large fish prey (i.e., Centracanthidae) usually occurs slightly before maturity--the life history stage with much higher energetic demands due to gonad gonad /go·nad/ (go´nad) a gamete-producing gland; an ovary or testis.gonad´algonad´ial indifferent gonad the sexually undifferentiated gonad of the early embryo. development (Ross, 1978). A similar pattern was observed for Atlantic cod (Gadus morhua) where sexual maturation and spawning are also associated with an ontogenetic change in diet (Paz et al., 1993). Thus, increased energy demands related to sexual requirements, gonad development, and breeding activity appear to be the critical factors driving the changes in feeding strategy of M. merluccius. In large hakes (>36 cm), cannibalism played an important role and should be carefully considered in stock-recruitment analyses. Studies carried out in the Mediterranean (Macpherson, 1977; Bozzano et al., 1997) and in the Atlantic (Guichet, 1995; Link and Garrison, 2002) showed that cannibalism has some importance for hake. In silver hake (M. bilinearis), cannibalism notably increased with ontogeny ontogeny: see biogenetic law. Ontogeny The developmental history of an organism from its origin to maturity. It starts with fertilization and ends with the attainment of an adult state, usually expressed in terms of both maximal body (Link and Garrison, 2002). In the large cape hakes, M. capensis, hake is the dominant food item (50% of the diet) for individuals larger than 60 cm (Roel and Macpherson, 1988). Conversely, a low cannibalism rate was observed for M. paradoxus in the same area (Payne et al., 1987). This could be a response to the greater accessibility of conspecifics compared to other species. As Payne et al. (1987) pointed out, small hake are not found in the vicinity of adults of the species. This is supported by the observed size segregation by depth, which is more pronounced in M. paradoxus than in M. capensis (Gordoa and Duarte, 1991). Density-dependent cannibalism may be an important source of natural mortality that can stabilize fish populations (Smith and Reay, 1991), and for M. capensis, cannibalism has even been considered the main cause of natural mortality (Lleonart et al., 1985; Payne and Punt, 1985). Our results on the trophic ecology Trophic ecology The study of the structure of feeding relationships among organisms in an ecosystem. Researchers focus on the interplay between feeding relationships and ecosystem attributes such as nutrient cycling, physical disturbance, or the rate of tissue of hake are of primary importance for future management of fish assemblages where this species plays an important predatory role. Multispecies management requires quantitative data on fish diet to elucidate the relationships between species and, consequently, to forecast temporal biomass fluctuations, under specific fishing regimes, in an integrated manner.
Table 1
Number of hakes and values of IRI (index of relative importance) (%)
for the nine size classes. The four groups identified from the cluster
analysis are indicated.
A B C
Size group I II III
Length (cm) 5.0-10.9 11.0-15.9 16.0-20.9
Number of hakes 202 430 564
Stomach contents 93 215 239
Prey
Cephalopoda
Alloteuthis media 0.22 0.02
Sepietta oweniana 0.02 0.02
Unid. Sepiolidae 0.35 0.30
Unid. Cephalopoda 0.42 0.10
Crustacea
Alpheus glaber 0.02 0.33
Aristeidae 0.01
Aristeus antennatus 0.02
Chlorotocus crassicornis 1.61 1.83
Crangonidae 0.01
Pandalidae 0.03
Parapenaeus longirostris
Pasiphaea multidentata 0.02
Pasiphaea sivado 0.20 0.04
Plesionika heterocarpus 0.11 0.01
Plesionika sp. 0.62 0.07
Pontocaris lacazei 0.01 0.02
Pontophilus spinosus 0.01 0.01
Processa sp. 0.25 0.06
Solenocera membranaca 0.04 0.02
Squilla sp.
Unid. Decapoda 3.05 19.91 6.19
Lophogaster typicus 28.77 4.34 0.16
Nictiphanes couchi 54.10 31.83 0.37
Unid. Euphasiacea 13.99 3.43 0.11
Unid. Isopoda 0.07 0.02 0.01
Pisces
Argentina sphyraena
Arnoglossuslaterna 0.01
Arnoglossus sp. 0.01
Callionymus sp. 0.01
Centracanthidae
Centracanthus cirrus
Clorophthalmus agassizi 0.01
Conger conger
Echiodon dentatus
Engraulis encrasicolus 1.95 11.61
Gadiculus argenteus
Gobiidae 0.04 0.02
Gobius quadrimaculatus 0.02
Lepidotrigla dieuzedei
Lesuerigobius friesii 0.01
Merluccius merluccius
Mullus barbatus
Myctophidae 0.30 0.28
Nettastoma melanurum 0.02
Sardina pilchardus 0.05 45.23
Sphyraena sphyraena
Spicara flexuosa
Spicara sp.
Trachurus trachurus
Trisopterus m. capelanus 0.02
Unid. Osteichthyes 0.04 34.19 33.14
Raja sp.
C
Size group IV V VI
Length (cm) 21.0-25.9 26.0-30.9 31.0-35.9
Number of hakes 454 555 224
Stomach contents 173 170 78
Prey
Cephalopoda
Alloteuthis media 0.01
Sepietta oweniana 0.01
Unid. Sepiolidae 0.03
Unid. Cephalopoda 0.01 0.02
Crustacea
Alpheus glaber 0.05 0.22 0.05
Aristeidae 0.02
Aristeus antennatus
Chlorotocus crassicornis 1.09 1.10 0.48
Crangonidae 0.01
Pandalidae 0.01
Parapenaeus longirostris 0.01
Pasiphaea multidentata 0.01
Pasiphaea sivado 0.05 0.02 0.05
Plesionika heterocarpus
Plesionika sp. 0.01 0.04 0.05
Pontocaris lacazei 0.01
Pontophilus spinosus 0.03 0.05 0.20
Processa sp. 0.06 0.15 1.77
Solenocera membranaca 0.05 0.34 0.58
Squilla sp. 0.05
Unid. Decapoda 2.84 2.73 1.45
Lophogaster typicus 0.01
Nictiphanes couchi
Unid. Euphasiacea
Unid. Isopoda
Pisces
Argentina sphyraena 0.08 0.41 1.06
Arnoglossuslaterna 0.01
Arnoglossus sp. 0.01 0.01
Callionymus sp. 0.01 0.01 0.06
Centracanthidae 0.03 0.11 2.60
Centracanthus cirrus 1.93
Clorophthalmus agassizi
Conger conger
Echiodon dentatus 0.05
Engraulis encrasicolus 1.28 4.45 9.91
Gadiculus argenteus 0.08 0.65
Gobiidae 0.01 0.01 0.05
Gobius quadrimaculatus 0.02 0.01
Lepidotrigla dieuzedei 0.01 0.01
Lesuerigobius friesii 0.02 0.03
Merluccius merluccius 0.07 0.18
Mullus barbatus 0.12
Myctophidae 0.03 0.15
Nettastoma melanurum 0.01 0.01
Sardina pilchardus 72.55 46.19 62.0
Sphyraena sphyraena
Spicara flexuosa 0.02 0.10 1.33
Spicara sp. 0.37
Trachurus trachurus 0.09 0.13
Trisopterus m. capelanus 0.01 0.01 0.05
Unid. Osteichthyes 21.61 43.44 15.01
Raja sp.
D
Size group VII VIII IX
Length (cm) 36.0-40.9 41.0-50.9 51.0-90.0
Number of hakes 139 107 75
Stomach contents 45 35 26
Prey
Cephalopoda
Alloteuthis media
Sepietta oweniana
Unid. Sepiolidae
Unid. Cephalopoda
Crustacea
Alpheus glaber 0.81 1.54
Aristeidae
Aristeus antennatus
Chlorotocus crassicornis
Crangonidae
Pandalidae
Parapenaeus longirostris
Pasiphaea multidentata
Pasiphaea sivado 0.33
Plesionika heterocarpus
Plesionika sp.
Pontocaris lacazei 0.20
Pontophilus spinosus
Processa sp. 0.83 1.54
Solenocera membranaca 3.27 3.53
Squilla sp.
Unid. Decapoda 1.58 1.32
Lophogaster typicus
Nictiphanes couchi
Unid. Euphasiacea
Unid. Isopoda
Pisces
Argentina sphyraena 4.04 3.29 2.34
Arnoglossuslaterna
Arnoglossus sp.
Callionymus sp.
Centracanthidae 2.43 11.23 53.97
Centracanthus cirrus 26.54 4.62 3.80
Clorophthalmus agassizi
Conger conger 0.34 0.85
Echiodon dentatus
Engraulis encrasicolus 0.87 1.27 1.86
Gadiculus argenteus 0.31 0.58
Gobiidae
Gobius quadrimaculatus
Lepidotrigla dieuzedei 0.78
Lesuerigobius friesii
Merluccius merluccius 12.00 4.10 17.95
Mullus barbatus 0.44 0.49
Myctophidae
Nettastoma melanurum
Sardina pilchardus 5.20 12.77 10.31
Sphyraena sphyraena 0.60 4.98
Spicara flexuosa 12.63 21.83 0.01
Spicara sp. 4.57 0.54 1.69
Trachurus trachurus 1.60 1.93
Trisopterus m. capelanus
Unid. Osteichthyes 23.09 22.90 4.25
Raja sp. 0.50
Literature cited Abella, A., J. F. Caddy A plastic container that holds a CD or DVD disc for added protection. The bare disc is placed in the caddy, and the caddy is inserted into the drive. A caddy is not a jewel case. A jewel case protects the disc for transportation. A caddy protects the disc while reading and writing. , and F. Serena. 1997. Do natural mortality and availability decline with age? An alternative yield paradigm for juvenile fisheries, illustrated by the hake Merluccius merluccius fishery in the Mediterranean. Aquat. Living. Resour. 10:1-14. Aldebert, Y., L. Recasens, and J. Lleonart. 1993. Analysis of gear interaction in a hake fishery: the case of the Gulf of Lions (NW Mediterranean). Sci. Mar. 57:207-217. Alheit, J., and T. J. Pitcher (eds.). 1995. Hake: fisheries, ecology and markets, 478 p. Chapman and Hall Chapman and Hall was a British publishing house, founded in the first half of the 19th century by Edward Chapman and William Hall. Upon Hall's death in 1847, Chapman's cousin Frederic Chapman became partner in the company, of which he became sole manager upon the retirement of , London. Alvarez, P., L. Motos, A. Uriarte, and J. Egana. 2001. Spatial and temporal distribution of European hake, Merluccius merluccius (L.), eggs and larvae Larvae, in Roman religion Larvae: see lemures. in relation to hydro-biological conditions in the Bay of Biscay Noun 1. Bay of Biscay - an arm of the Atlantic Ocean in western Europe; bordered by the west coast of France and the north coast of Spain Atlantic, Atlantic Ocean - the 2nd largest ocean; separates North and South America on the west from Europe and Africa on the east . Fish. Res. 50:11-128. Andaloro, F., P. Arena, and S. Prestipino Giarritta. 1985. Contribution to the knowledge of the age, growth and feeding of hake Merluccius merluccius (L. 1758) in the Sicilian channel. FAO FAO, n See Food and Agriculture Organization. Fish Rep. 336:93-97. Ardizzone, G. D., and F. Corsi. 1997. Atlas of Italian demersal fishery resources. Biol. Mar. Medit. 4(2), 568 p. Arneri, E., and B. Morales-Nin. 2000. Aspects of the early life history of European hake from the central Adriatic. J. Fish. Biol. 53:1155-1168. Beamish, F. W. H. 1966. Vertical migration of demersal fish in the northwest Atlantic. J. Fish. Res. Board Can. 23: 109-139. Bouaziz, A., F. Djabali, and C. Maurin. 1990. Regime alimentaire du merlu (Merluccius merluccius, L., 1758) en bale de Bou Ismail. Rapp. Comm. int. Met Medit. 32(1) :273. Bowman, R. E., and E. W. Bowman. 1980. Diurnal diurnal /di·ur·nal/ (di-er´nal) pertaining to or occurring during the daytime, or period of light. di·ur·nal adj. 1. Having a 24-hour period or cycle; daily. 2. variation in the feeding intensity and catch-ability of the silver hake (Merluccius bilinearis). Can. J. Fish. Aquat. Sci. 37:1562-1572. Bozzano, A., L. Recasens, and P. Sartor. 1997. Diet of the European hake Merluccius merluccius (Pisces: Merlucciidae) in the Western Mediterranean (Gulf of Lions). Mar. Sci. 61(1):1-8. Buchholz, F, C. Buchholz, J. Reppin, and J. Fischer. 1995. Diel vertical migration Diel vertical migration refers to a pattern of movement that some organisms living in the ocean's photic zone undertake each day. The organisms that exhibit this pattern of behaviour range in size from microscopic plankton through to much larger nekton such as fish. of Meganyctiphanes norvegica in the Kattegat: comparison of net catches and measurements with acoustic Doppler current profilers. Helgol. Wiss. Meeresunters 49:849-866. Casanova, B. 1970. Repartition re·par·ti·tion n. 1. Distribution; apportionment. 2. A partitioning again or in a different way. tr.v. re·par·ti·tioned, re·par·ti·tion·ing, re·par·ti·tions To partition again; redivide. bathymetrique des euphausiaces dans le bassin occidental de la Mediterranee. Rev. Trav. Inst. Peches Marit. 34(2):205-219. Clarke, K. R., and R. M. Warwick. 1994. Change in marine communities: an approach to statistical analysis and interpretation, 144 p. Natural Environment Research Council, UK. Colloca, F., A. Belluscio, and G. D. Ardizzone. 2000. Sforzo di pesca, cattura e gestione dello stock di nasello (Meluccius merluccius) in un'area del tirreno centrale. Biol. Mar. Medit. 7(1):117-129. Colloca, F., P. Gentiloni, A. Belluscio, P. Carpentieri, and G. D. Ardizzone. 2002. Estimating growth parameters of the European hake (Merluccius merluccius) through the analysis and validation of annual increments in otoliths. Arch. Fish. Mar. Res. 50 (2):174-179. Fisher, W., W. M. Bauchot, and M. Schneider. 1987. Fiches FAO d'identification pour les besoins de la peche revision 1. Mediterranee et mer Noire. Zone de peche 37, vol. 2: Vertebres, p. 761-1530. FAO, Rome. Flamigni, C. 1984. Preliminary utilization of trawl survey data for hake (Merluccius merluccius, L.) population dynamics Population dynamics is the study of marginal and long-term changes in the numbers, individual weights and age composition of individuals in one or several populations, and biological and environmental processes influencing those changes. in the Adriatic Sea Adriatic Sea (ādrēă`tĭk), arm of the Mediterranean Sea, between Italy and the Balkan Peninsula. It extends c.500 mi (800 km) from the Gulf of Venice, at its head, SE to the Strait of Otranto, which leads to the Ionian Sea. . FAG Fish. Rep. 290:109-115. Franqueville, C. 1971. Macroplancton profond (invertebres) de la Mediterrange nord-occidentale. Tethys 3(1):11-56. Froglia, C. 1973. Osservazioni sull'alimentazione del merluzzo (Merluccius merluccius L.) del Medio Adriatico. In Atti V Congresso Naz. Soc. It. Biol. Mar. (N. Salentina, ed.), p. 327-341. Gordoa, A., and C. M. Duarte. 1991. Internal school density of Cape hake (Merluccius capensis). Can. J. Fish. aquat. Sci. 48:2095-2099. Guichet, R. 1995. The diet of European hake (Merluccius merluecius) in the northern part of the Bay of Biscay. ICES J. Mar. Sci. 52:21-31. Hacunda, J. S. 1981. Trophic relationships among demersal fishes in a coastal area of the Gulf of Maine The Gulf of Maine is a large gulf of the Atlantic Ocean on the northeastern coast of North America. It is delineated by Cape Cod at the eastern tip of Massachusetts in the southwest and Cape Sable at the southern tip of Nova Scotia in the northeast. . Fish. Bull. 79: 775-788. Hickling, C. F. 1927. The natural history of the hake. Parts I and II. Fish. Invest. Serv. II, 10 (2), 112 p. Holden, M. J., and D. F. S. Raitt. 1974. Manual of fisheries science. Part 2: Methods of resources investigation and their application FAO Fish. Tech. Paper 115, 214 p. FAO, Rome. Hyslop, E. J. 1980. Stomach content analysis: a review of methods and their application. J. Fish Biol. 17:411-429. Jukic, S., and E. Arneri. 1984. Distribution of hake (Merluccius merluccius, L.) striped mullet (Mullus barbatus, L.) and pandora (Pagellus erythrinus, L.) in the Adriatic Sea. FAO Fish. Rep. 290:85-91. Lleonart, J., J. Salat Noun 1. salat - the second pillar of Islam is prayer; a prescribed liturgy performed five times a day (preferably in a mosque) and oriented toward Mecca salaah, salaat, salah worship - the activity of worshipping , and E. Macpherson. 1985. CVPA CVPA College of Visual and Performing Arts CVPA Center for Visual and Performing Arts CVPA Cache Valley Pagan Alliance , an expanded VPA VPA Valproate VPA Vancouver Port Authority (Canada) VPA Virtual Population Analysis VPA Voluntary Partnership Agreement VPA Voluntary Placement Agreement VPA Volume Purchase Agreement VPA Vermont Principals' Association with cannibalism. Application to a hake population. Fish. Res. 12:119-146. Link, J. S., and L. P. Garrison. 2002. Changes in piscivory associated with fishing induced changes to the finfish finfish fish with fins, that is teleosts, elasmobranches, holocephalids, agnathids and cephalochordates; also a fish marketer's term used to include that section of marketable fish which is neither shellfish nor molluscs. community on Georges Bank. Fish. Res. 55:71-86. Macpherson, E. 1977. Estudio sobre relaciones troficas en peces bentonicos de la costa catalana. Ph.D. diss., 369 p. Universitat de Barcelona, Barcelona. Oliver, P., and E. Massuti. 1995. Biology and fisheries of western Mediterranean hake(M. merluccius). In Fish and fisheries series 15, hake, fisheries, ecology and markets (J. Alheit and T. J. Pitcher), p. 181-202. Chapman and Hall, London. Orsi Relini, L., F. Fiorentino, and A. Zamboni. 1989. Spatial-temporal distribution and growth of Merluccius merluccius recruits in the Ligurian Sea. Observations on the O group. Cybium (13):263-270. Papaconstantinou, C., and E. Caragitsou. 1987. The food of hake (Merluccius merluccius) in Greek Seas. Vie Milieu 37:77-83. Payne, A. I. L., B. Rose, and R. W. Leslie. 1987. Feeding of hake and a first attempt at determining their trophic role in the South African west coast marine environment, in The Benguela and comparable ecosystem (A. I. L. Payne, J. A. Gulland and K. H. Brink, eds.). S. Afr. J. Mar. Sci. 5:471-501. Payne, A. I. L., and A. E. Punt. 1985. Biology and fisheries of South African cape hakes (M. capensis and M. paradoxus). Hake--fisheries, ecology and markets. Chapman and Hall, London. Paz, J., J. M. Casas, and G. Perez-Gandaras. 1993. The feeding of cod (Gadus morhua) on Flemish Cap, 1989-90. NAFO NAFO Northwest Atlantic Fisheries Organization NAFO Network Adapter Failover (Sun Microsystems) NAFO National Association of Fire Officers (UK) NAFO National Association of Fire Officials Scientific Council Studies 19, p. 41-50. Pinkas, L., M. S. Oliphant, and I. L. K. Iverson. 1971. Food habits of albacore albacore: see tuna. albacore Large oceanic tuna (Thunnus alalunga) that is noted for its fine flesh. The streamlined bodies of these voracious predators are adapted to fast and continuous swimming. , bluefin tuna and bonito bonito: see mackerel. bonito Swift, predaceous schooling fishes (genus Sarda) of the mackerel family (Scombridae). Bonitos, found worldwide, have a striped back and silvery belly and grow to about 30 in. (75 cm) long. in California waters. Calif. Dep. Fish Game Fish. Bull. 152:1-150. Recasens, L., A. Lombarte, B. Morales-Nin, and G. J. Torres. 1998. Spatiotemporal spa·ti·o·tem·po·ral adj. 1. Of, relating to, or existing in both space and time. 2. Of or relating to space-time. [Latin spatium, space + temporal1. variation in the population structure of the European hake in the NW Mediterranean. J. Fish. Biol., 53:387-401. Relini, G., and C. Piccinetti. 1996. Ten years of trawl surveys in Italian seas (1985-1995). FAO Fish. Rep. 533:21-41. Relini, G., J. Bertrand, and A. Zamboni. 1999. Synthesis of the knowledge on bottom fishery resources in central Mediterranean (Italy and Corsica). Biol. Mar. Medit. 6, 868 p. Roel, B., and E. Macpherson. 1988. Feeding of Merluceius capensis and M. paradoxus off Namibia. S. Afr. J. Mar. Sci. 6:227-643. Ross, S. T. 1978. Trophic ontogeny of the leopard searobins, Prionotus scitulus (Pisces: Triglidae). Fish. Bull. 76:225-234. Sarano, F. 1986. Cycle ovarien du Merlu, Merluccius merluccius, poisson a ponte fractionnee. 2ev. Trav. Inst. Peches Marit. 48:65-67. Smith, C., and P. Reay. 1991. Cannibalism in teleost fish. Rev. Fish Biol. Fish 1:41-64. Vallet, C., and J. C. Dauvin. 2001. Biomass changes and bentho-pelagic transfers throughout the Benthic Boundary Layer in the English Channel. J. Plankton plankton: see marine biology. plankton Marine and freshwater organisms that, because they are unable to move or are too small or too weak to swim against water currents, exist in a drifting, floating state. Research, vol. 23(9):903-922. Velasco, F., and I. Olaso. 1998. European hake Merluccius merluccius (L., 1758) feeding in the Cantabrian Sea: seasonal, bathymetric ba·thym·e·try n. The measurement of the depth of bodies of water. bath  y·met and length variations. Fish. Res.
38:33-44.
Manuscript submitted 27 April 2003 to the Scientific Editor's Office. Manuscript approved for publication 13 December 2004. Paolo Carpentieri Francesco Colloca Department of Animal and Human Biology University "La Sapienza" Viale dell'Universita 32 00185 Rome, Italy E-mail address (for P. Carpentieri): paolo.carpentieri@uniroma1.it Massimiliano Cardinale Institute of Marine Research National Board of Fisheries P.O. Box 4 45 332, Lysekil, Sweden Andrea Belluscio Giandomenico D. Ardizzone Department of Animal and Human Biology University "La Sapienza" Viale dell'Universita 32 00185 Rome, Italy |
|
||||||||||||||||||
Printer friendly
Cite/link
Email
Feedback
Reader Opinion