Studies on the systematics, biology and fishery of rainbow sardines, dussumieria spp., from Indian waters

Rainbow sardines of the genus belonging to the family Dueenaieriidae. are small pelagic fishes forming a fairly good, though not abundant. seasonal fishery all along the coasts of India inhabiting the coastal waters. There have been some earlier reports on such individual aspects as their systematic, distribution, abundance. Ostecology and a few biological factors but no attempt has been made towards a comprehensive study on this group. Two species of rainbow sardines are known to occur in the Indian seas and while a knowledge about their biology would be useful from the fishery point of view. it was also thought a study of their systematic position, especially regarding the identity or the two species which had raised doubts among earlier workers would lead to a better understanding or the group as a whole. This thesis is mainly based on studies during the period from April 1969 to march 1971 with a continued investigation of fishhery aspects till December 1975. from the Gulf of manar: and the Palk Bay around mandapam area. on the south-east coast of India. Thus the work deals with the systemtics, biology and fishery of rainbow sardines of Indian seas.

Preliminary data on horse mackerel (Trachurus spp) landings from Mauritanian waters

European fishery off Mauritania (one of the most productive and most intensively exploited regions in the world) targeted to small pelagic fish accounts for 30% of the total catches in the area. The Instituto Español de Oceanografía (IEO), through its Centro Oceanográfico de Canarias, follows up the activity of these vessels that land at Spanish port (Las Palmas de Gran Canaria, Spain), under the European Project Data Collection (Regulation (EC) 1543/2000). One of the target groups in this fishery is Trachurus spp, commercially named “JAX”. During 2008 and 2009, several samples of this group from these landings were analysed, and Caranx rhonchus was the second species of importance. The mixture of these species in the landings of this UE fleet should be determined to improve the data provided to the international Working Groups responsible for assessment of those resources.

A histopathologic evaluation of gross lesions excised from commercially important North Altantic marine fishes

Histopathologic studies of lesions found in commercially important North Atlantic marine fishes are uncommon. As part of a comprehensive Northeast Fisheries Center program ("Ocean Pulse") to evaluate environmental and resource health on the U.S. Continental Shelf from Cape Hatteras to Nova Scotia, grossly visible lesions of the gills, integument, muscle, and viscera of primarily bottom-dwelling fishes were excised and examined using light microscopy. Several gadid and pleuronectid fishes accounted for most of the lesions observed. Most pathological examinations were incidental to samples taken for age and growth determination and evaluation of predator/prey relationships. Several gadids, with either gill, heart, or spleen lesions, were sampled more intensively. Gill lesions principally affected gadids and were caused by either microsporidans or an unidentified oocyte-like cell. The majority of gastrointestinal lesions consisted of encapsulated or encysted larval worms or microsporidan-induced cysts. Few heart lesions were found. Integumental lesioos included ulcers, lymphocystis, and trematode metacercariae. Liver lesions almost always consisted of encapsulated or encysted larval helminths. Necrotic granulomata were seen in muscle and microsporidan-induced granulomata in spleen. Although not numerous, histologically interesting lesions were noted in integument, heart, liver, spleen, and muscle of several fish species. Histologic study of tissues excised from a variety of demersal and pelagic fishes from the eastern North Atlantic (France, Germany, Spain) revealed assorted integumental, renal, hepatic, and splenic lesions. Small sample size and non-random sampling precluded obtaining a meaningful quantitative estimate of the prevalence of the observed lesions in the population at risk; however, a useful census has been made of the types of lesions present in commercially important marine fishes. (PDF file contains 20 pages.)

Present status and potentials of inshore and offshore pelagic fisheries in the capture and processing industries of Nigeria

Apart from activities of some foreign-based vessels, commercial exploitation of pelagic fishery resources in Nigeria has been limited to inland and inshore waters. Estimated potential for the inshore pelagic fishery is 70,000-90,000 tonnes while the small pelagic resources in the near offshore as well as tuna and tuna-like fishes further offshore have potentials of about 10,000 metric tonnes each. Despite the abundance of tuna within and adjoining the Nigerian EEZ, and its importance in the international market, only foreign-flagged vessels take advantage. In addition, the inshore pelagic fisheries in Nigeria have for long remained underexploited. The most common processing method has remained the age-old traditional smoke-drying, which is inadequate resulting in colossal waste through denaturation and incessant infestations by insects and moulds among other causes. The use of modern smoking techniques coupled with effective distribution systems can undoubtedly reduce waste. However, these are often not within the reach of most artisanal processors. It is proposed that the organised private sector should invest on simple but proven processing equipment such as smoking kilns. The inshore pelagic fish species and other small fishes can sustain cottage canning industries sited in fishing villages/settlements while larger canning factories should be based on offshore resources. Modalities for successful investments are highlighted, while a major consideration is given to joint ventures

Diet composition and food habits of demersal and pelagic marine fishes from Terengganu waters, east coast of Peninsular Malaysia

Fish stomachs from 18 demersal and pelagic fishes from the coast of Terengganu in Malaysia were examined. The components of the fishes’ diets varied in number, weight, and their frequency of occurrence. The major food items in the stomachs of each species were determined using an Index of Relative Importance. A conceptual food web structure indicates that fish species in the study area can be classified into three predatory groups: (1) predators on largely planktivorous or pelagic species; (2) predators on largely benthophagous or demersal species; and (3) mixed feeders that consume both pelagic and demersal species.

Pelagic fishery resources of Sri Lanka and its present level of exploitation with special reference to off-shore and deep-sea waters

Pelagic resources around Sri Lanka may be categorized into three major groups: (1) the small pelagic varieties such as the sprats, halmessa, sardines (salaya, soodaya), and herrings (hurulla). (2) the medium size pelagic species such as the mackerel (kumbala and bolla), barracuda (jeela), seer Spanish mackerel (thora), frigate mackeral (alagoduwa), mackerel tuna (atawalla) and the skipjack (balaya). (3) the large size fishes such as yellow fin tuna (kelawalla), big eye tuna, marlins (koppora and gappara), sail fish (thalapath), sharks (mora) and rays (maduwa). Production levels of exploited resources are noted, and seasonal patterns and annual in their abundance are considered. On the basis of observations and estimations of the existing fisheries, and the results of experimental fishing, figures are presented of the potential yield of those species already exploited. The development of that potential depends on the development of modern techniques of pole and line fishing, application of tuna longline and shark longline, increasing the number of units of drift nets and the introduction of a bait fishery for the longline and pole line fishery. Some features upon which the successes of any venture to exploit such resources are noted, particularly those which relate to the nature of the fishing vessels used.

Observations of the 1992 U.S. Pelagic Pair Trawl Fishery in the Northwest Atlantic

Pelagic pair trawling for tuna, Thunnus spp., and swordfish, Xiphias gladius, was introduced in U.S. Northwest Atlantic waters in 1991. During autumn (October-November) of 1992 under the authority oft he Federal Atlantic Swordfish Regulations, the National Marine Fisheries Service placed observers aboard pelagic pair trawl vessels to document the catch, bycatch, discard, and gear used in this new fishery. The fishery is conducted primarily at night along shelf-edge waters from June to November. In late 1991, revised regulations restricted swordfish to bycatch in this fishery resulting in pelagic pair trawl vessels targeting tuna throughout 1992. Analyses of 1992 data indicate that albacore, T. alalunga, was the predominant species caught, although yellowfin tuna, T. albaeares, and bigeye tuna, T. obesus, were the preferred target species. Bycatch also included swordfish, large sharks, pelagic rays and other pelagic fishes, other tunas, and marine mammals.

The Commercial, Subsistence, and Recreational Fisheries of American Samoa

Domestic fisheries in American Samoa landed 587,000 lb of fish and invertebrates in 1991 worth $993,000. Most of the catch (78%) and value (80%) was taken by the shoreline subsistence fishery that occurs on the coral reefs surrounding the islands. Artisanal fisheries for offshore pelagic fishes (primarily skipjack tuna, Katsuwonus pelamis; and yellowfin tuna, Thunnus albacares) and bottomfishes (snappers, emperors, groupers) accounted for 16% and 3%, respectively, of the domestic catch. Recreational tournament catches for pelagic fishes represented the remainder (3%). While sportfishing is becoming increasingly important, other domestic fisheries have declined in recent years. The shoreline subsistence fishery has dropped by about 25% over the past decade owing to socioeconomic factors and possibly overexploitation. Artisanal fisheries have also declined precipitously in recent years owing to hurricane-related damages, attrition of fishermen, and competition with imports. Artisanal fisheries show some potential for growth, but may be constrained by marketing issues, vessel capabilities, and limited stock sizes (for bottomfish) or local availability of high-value (pelagic) fishes. In contrast to the small-scale domestic fisheries, American Samoa is also homeport to a distant-water fleet of large purse seiners and longliners that fish beyond the EEZ and deliver about 160,000-220,000 short tons of tuna per year to local canneries.

Nutritional value of some small indigenous fish species (SIS) of Bangladesh

Twenty three small indigenous fish species (SIS) in the size range of 3-18 cm were analyzed for proximate composition and minerals (Ca and P) content to evaluate their nutritive value. The moisture content of different species ranged between 71.00 and 81.94%. In general, small sized fishes showed higher moisture content. The muscle protein content among the species varied widely (16.16-22.28%). In general, the muscle protein content of fishes showed higher value than the whole carcass protein content. The carcass lipid content varied between 1.87 and 9.55% and showed an inverse relationship with the moisture content. The gross energy content ranged from 19.51-27.30 KJ/g on dry matter basis. In the present study, the calcium and phosphorus contents ranged between 0.85-3.20% and 1.01-3.29% respectively. The calcium and phosphorus ratio (Ca/P) varied between 0.44 and 2.00. From the nutritional point of view, it shows that the SIS are good source of protein and minerals especially calcium and phosphorus

Report of Catch Assessment Survey of Lake Albert – Albert Nile conducted in July 2012

A Catch Assessment Surveys (CAS) with the overall objective of generating information on the fish production and commercial value of the fisheries of Lake Albert and Albert Nile system was implemented by the National Fisheries Resources Research Institute (NAFIRRI) in collaboration with the Department of Fisheries Resources (DFR), Local Government staff (FOs) and BMU members at selected landing sites on Lake Albert (12 landing sites) and Albert Nile (26 landing sites) in July 2012. A total 622 and 313 boat days on Lake Albert and Albert Nile respectively were sampled for a period of 9 days. Results indicate an annual landing of 151,600 and 5,900 tonnes (t) of fish with an estimated beach value of 122.5 and 14 Billion (UShs) from Lake Albert and Albert Nile respectively. Over 80% of the catch from Lake Albert comprised the small pelagic species; Neobola bredoi (Muziri) and Brycinus nurse (Ragoogi) followed by Nile perch (6%). However, due to low market value of the small fishes and the high prices attached to Nile perch for industrial processing and export market, the contribution of the latter to beach value rose to 34% of the total. The contribution of the light fishery based on small pelagic species (B. nurse and N. bredoi) are insignificant on Albert Nile. Even if the small pelagic species may be present in the river system, a light fishery based on these two is yet to be developed. Proportionally, Albert Nile still remain a multispecies fishery with over 20 fish species harvested commercially. Interestingly, the Albert Nile fishery still remains primitive with simple crafts and gears (mainly dugout canoes, traps, and gillnets). This could suggest that the more developed the system becomes the higher the level of transformation in its fisheries leading to simplification, characterized by reduction in multispecies nature and dominance of few species. Illegal gears especially undersized gillnet of mesh size less than 4 inches were the most dominant in the Lake Albert and Albert Nile fisheries. They captured large quantities of immature fish particularly when used to target Nile perch, Bagrus, Nile tilapia, and large Barbus spp. Their impact when used to target the smaller species (Ragoogi, Angara & Ngasia) is yet to be evaluated. A specific study to analyze selectivity and impacts of these nets is a recommended. However, the dominance of 1.5” mesh sizes especially on Albert Nile to target Angara, Ngassia and Barbus, is definitely destructive to their fisheries and should be checked forthwith. In addition, there is an emerging fishing method locally referred to as “Salsio or Luzira” whereby fishers stay on the lake from 3 days up to 2 weeks without returning to the landing site. They carry with them food and salt for processing the catches on the lake, and in the case of Albert Nile on make shift shelters on islands and in the game park. They normally use gillnets of 3-3½ inch mesh size and caught mainly Nile perch & Bagrus (Pethi & Munama). On return they land several tons of fish. Most of these Catches are not captured in the estimates presented in our analyses since we target daily fishing boats. The possible impacts of this fishing method should be studied and appropriate action recommended.

Coastal fisheries

The coastal zone of Sri Lanka is the most important area of fish production at present. This coastal zone is limited seawards to the edge of our relatively narrow continental shelf. The fishing methods employed are such that only a fraction of the shelf area is exploited. The extent to which the coastal zone is exploited depends on the craft and gear used in the fishing operations. The non-mechanized traditional crafts such as the teppams and orus generally operate within about five miles from shore. The mechanized traditional crafts and the small mechanized boats introduced around 1957 carry out fishing operations up to the continental shelf or beyond. The gear used by these fishing crafts is determined by the habits of the type of fish to be caught, the nature of the sea bed and other related conditions. For the pelagic fishes they use trolling lines or float long lines or drift nets. For the demersal fishes hand lines, bottom long lines, bottom set nets or drag nets are used. However, the net is the preferred fishing gear. The beach seines or madels, the traditional crafts such as orus, teppams and vallams and the small mechanized boats are the important contributors in the coastal fishery. Of these the madels are considered the most important since a high percentage (25-35%) of the Island's landings are produced by the operation of these nets.

Nutritional evaluation of some small coastal fish in Sri Lanka

Small pelagic fish play a very important role in human nutrition and health. Lipids of these fish differ remarkably from plant and other animal lipids. The aim of the study was to describe the proximate composition of thirty-three small pelagic fish species commonly available in Sri Lanka. Fish species were collected from Negombo and Chillaw fish landing sites and subjected to analysis for moisture, ash, protein and total lipid content. Tiger tooth croaker (Otolithus ruber) was found to have the highest moisture percentage (80.0%) followed by Clarias sp. (78.9%), Indian anchovy (Steloporus indicus) and Comerson's anchovy (Stelophorus commersonii), (78%). The lowest percentage of moisture, 69.4%, was recorded in white sardinella (Sardinella albella). Indian ilisha (Ilisha melastoma) was found to have the highest amount of ash (10.1%) followed by Otolithus sp. (8%) and big-eye barracuda contained the least amount (2.5%). Carassius Carassius, pick handle barracuda (Sphyraena jello) and Indian mackerel (Rastrelliger kanagurta) contained higher amounts of protein, 24.3, 20.6 and 19.2% respectively. The lowest protein content (10.1%) was found in Indian scad (Decapterus russelli). The protein content of the fish was in the range of 13-15%. The results revealed that the small fish are moderate protein sources. The total lipid content varied between 0.6-8%. White sardinella recorded the highest percentage of lipid (8%) where tiger tooth croaker contained the lowest percentage (0.6 %). The study showed high fatty species to contain low amount of moisture and vice versa establishing an inverse relation between fat and moisture quantitatively.

Biology, ecology and the fishery of Mukene, Rastrineobola argentea

Food and feeding, condition factor, breeding periods, growth and size at first maturity of a small pelagic cyprinid Rastrineobola argentea (P.) in Lake Victoria are determined. Fishing gears and methods that have been used in the exploitation of the species and could be harmful to the fishery are outlined. Management measures leading to possible sustainable exploitation of the fishery are suggested. Adult R. argentea feed on zooplankton during daytime. Juveniles feed on planktonic early instars of lakefly larvae. Although the species breeds throughout the year, two breeding peaks were observed during the drier months of August and December January. Least breeding was observed in the rainy months of April-May and October November. Fishes from the open water station at Bugaia showed higher numbers of breeding individuals than those from inshore areas. The mean monthly condition factor of fish from Napoleon Gulf confirmed breeding peaks as obtained from the number of fish with ripe gonads. The species showed a mean instantaneous growth rate (K) of 1.75 and attains length infinity (Lx) of 54mm. Females of the species in these waters show a reduced size at maturity as compared to ten years ago when exploitation of the species was at minimal levels. The males have however not changed much.

Variation in stable isotope signatures of seston and a zooplanktivorous fish in a eutrophic Chinese lake

Temporal and spatial changes in delta(13)C and delta(15)N of seston (mainly phytoplankton) and isotopic relationship between seston and the lake anchovy (Coilia ectenes) were studied in the large eutrophic freshwater Lake Chaohu in China. Much of the spatial and temporal variation in delta(13)C of lake anchovies was explained by variation in seston, indicating a strong link between pelagic primary production and higher order consumers. Because the lake is shallow, there were no significant differences in delta(13)C and delta(15)N of seston between surface and overlying waters. Spatially, the relatively high delta(13)C and delta(15)N of seston in the western part of the lake might be due to high levels of anthropogenically derived N and C introduced from the surrounding cities through sewage drainage systems. The trophic position of the lake anchovy in the food web of Lake Chaohu was estimated to be 2.9-4.1 (3.5 +/- 0.4), which agrees well with the previous stomach content analysis suggesting that the lake anchovy fed both on zooplankton and small planktivorous fishes.

SNP discovery using Next Generation Transcriptomic Sequencing in Atlantic herring (Clupea harengus)

The introduction of Next Generation Sequencing (NGS) has revolutionised population genetics, providing studies of non-model species with unprecedented genomic coverage, allowing evolutionary biologists to address questions previously far beyond the reach of available resources. Furthermore, the simple mutation model of Single Nucleotide Polymorphisms (SNPs) permits cost-effective high-throughput genotyping in thousands of individuals simultaneously. Genomic resources are scarce for the Atlantic herring (Clupea harengus), a small pelagic species that sustains high revenue fisheries. This paper details the development of 578 SNPs using a combined NGS and high-throughput genotyping approach. Eight individuals covering the species distribution in the eastern Atlantic were bar-coded and multiplexed into a single cDNA library and sequenced using the 454 GS FLX platform. SNP discovery was performed by de novo sequence clustering and contig assembly, followed by the mapping of reads against consensus contig sequences. Selection of candidate SNPs for genotyping was conducted using an in silico approach. SNP validation and genotyping were performed simultaneously using an Illumina 1,536 GoldenGate assay. Although the conversion rate of candidate SNPs in the genotyping assay cannot be predicted in advance, this approach has the potential to maximise cost and time efficiencies by avoiding expensive and time-consuming laboratory stages of SNP validation. Additionally, the in silico approach leads to lower ascertainment bias in the resulting SNP panel as marker selection is based only on the ability to design primers and the predicted presence of intron-exon boundaries. Consequently SNPs with a wider spectrum of minor allele frequencies (MAFs) will be genotyped in the final panel. The genomic resources presented here represent a valuable multi-purpose resource for developing informative marker panels for population discrimination, microarray development and for population genomic studies in the wild.