An analysis of salmon rod catch data from castle fisheries, River Derwent, 1923-1989.

The aim of this study was to investigate the historical catch record from the Castle Fishery on the River Derwent over the period 1923 - 1989, to determine if changes had taken place in the composition of the catch and to examine the influence of flow on the performance of the fishery. The River Derwent is situated in West Cumbria, North West England. It flows from its source on Scafell Pike (NGR NY 229 089) westwards discharging into the Irish sea at Workington, a distance of 52 km. Over its length it receives water from an additional 214 km of stream, 5 large lakes and approximately 30 small tarns. The catchment drains a total area of 663 km2. The study concludes that through the time period there was considerable variation in catch between years. The trend was for the catch to increase steadily over the period 1923 - 1958, declining rapidly in 1959, after which catches increased steadily reaching a peak in the mid-sixties, before declining towards the end of the decade. During the seventies and eighties catches remained relatively stable at between 300 - 600 salmon per year until 1988 when over 2000 salmon were reported caught, the greatest number in any year over the study period.

A new species of western Atlantic lizardfish (Teleostei: Synodontidae: Synodus) and resurrection of Synodus bondi Fowler, 1939, as a valid species from the Caribbean with redescriptions of S. bondi, S. foetens (Linnaeus, 1766), and S. intermedius (Agassiz, 1829)

Western Atlantic synodontid species were studied as part of an ongoing effort to reanalyze Caribbean shorefish diversity. A neighbor-joining tree constructed from cytochrome c oxidase I (COI) data revealed 2 highly divergent genetic lineages within both Synodus intermedius (Agassiz, 1829) (Sand Diver) and S. foetens (Linnaeus, 1766) (Inshore Lizardfish). A new species, Synodus macrostigmus, is described for one of the S. intermedius lineages. Synodus macrostigmus and S. intermedius differ in number of lateral-line scales, caudal pigmentation, size of the scapular blotch, and shape of the anterior-nostril flap. Synodus macrostigmus and S. intermedius have overlapping geographic and depth distributions, but S. macrostigmus generally inhabits deeper water (>28 m) than does S. intermedius and is known only from coastal waters of the southeastern United States and the Gulf of Mexico, in contrast to those areas and the Caribbean for S. intermedius. Synodus bondi Fowler, 1939, is resurrected from the synonymy of S. foetens for one of the S. foetens genetic lineages. The 2 species differ in length and shape of the snout, number of anal-fin rays, and shape of the anterior-nostril flap. Synodus bondi and S. foetens co-occur in the central Caribbean, but S. bondi otherwise has a more southerly distribution than does S. foetens. Redescriptions are provided for S. intermedius, S. foetens, and S. bondi. Neotypes are designated for S. intermedius and S. foetens. A revised key to Synodus species in the western Atlantic is presented.

Population dynamics of the ribbon fish, Lepturacanthus savala (Cuvier 1829) from the north-eastern part of the Bay of Bengal

Population parameters of Lepturacanthus savala from the trawl catches in the north-eastern part of the Bay of Bengal, Bangladesh were investigated based on length frequency data, using complete ELEFAN computer program. The asymptotic length (Lα) and growth constant (K) were estimated to be 106.50 cm (total length) and 0.80/year respectively. Based on these growth parameters, the total mortality (Z) was estimated to be 1.89. The estimated values for natural mortality (M) and fishing mortality (F) were 1.08 and 0.81 respectively. The estimated value for the exploitation rate (E) using the length converted catch curve was 0.43. The recruitment pattern showed two peaks per year. The estimated sizes of L. savala at 25, 50 and 75% probabilities of capture were 57.49, 60.39 and 63.28 cm respectively. The estimated length weight relationship for combined sex was W=0.00093 TL(super)2.97

Growth parameters of Lepturacanthus savala (Cuvier, 1829) from Mumbai waters

Lepturacanthus savala (Cuvier, 1829) constitutes a minor fishery contributing 23.3% to the total ribbonfish catch in Maharashtra. Based on the length data obtained from shrimp trawlers and the traditionally operated bag nets, age and growth of the species have been investigated from Mumbai waters. Growth was studied by various computer-based methods incorporated in FiSAT Programme. The growth parameters L∞ and K (on annual basis) by Gulland-Holt plot were 683.3 mm and 0.87, respectively. As the seasonal temperature variations in coastal waters of Mumbai are not pronounced, the seasonally oscillating growth patterns by ELEFAN and Appledoorn's method were not considered. Following the von Bertalanffy growth model, the fish attains 399.8, 567.2 and 637.4 mm at the end of 1, 2 and 3 years, respectively, and the lifespan of the fish is about 3.3 years.

Reproduction, age and growth of the kelee shad, Hilsa kelee (Cuvier, 1829) (pisces: fam. Clupeidae) with informations on its fishery in Maputo Bay, Mozambique

Age, growth and reproduction of H. kelee were studied, and a brief description of its fishery in Maputo Bay (Mozambique) is given. Most material was collected from gill net fisheries during 1977-1980, but some was taken from shrimp trawlers operating in the same area during 1980-1981. Main spawning takes place during October-January with a peak in December. There is also some evidence that spawning takes place during June-July. The size at first maturity was approximately equals 14-15 cm. Ageing was carried out using primary growth rings in the otoliths and length-frequency analysis of fish caught by shrimp trawlers. Von Bertalanffy's growth equation parameters were determined. Males and females grew in similar fashion. There are seasonal trends in the catch composition of the gill net fishery, showing high values during April to September and low during October to December.