Radiometric validation of age, growth, and longevity for the blackgill rockfish (Sebastes melanostomus)

As nearshore fish populations decline, many commercial fishermen have shifted fishing effort to deeper continental slope habitats to target fishes for which biological information is limited. One such fishery that developed in the northeastern Pacific Ocean in the early 1980s was for the blackgill rockfish (Sebastes melanostomus), a deep-dwelling (300−800 m) species that congregates over rocky pinnacles, mainly from southern California to southern Oregon. Growth zone-derived age estimates from otolith thin sections were compared to ages obtained from the radioactive disequilibria of 210Pb, in relation to its parent, 226Ra, in otolith cores of blackgill rockfish. Age estimates were validated up to 41 years, and a strong pattern of agreement supported a longevity exceeding 90 years. Age and length data fitted to the von Bertalanffy growth function indicated that blackgill rockfish are slow-growing (k= 0.040 females, 0.068 males) and that females grow slower than males, but reach a greater length. Age at 50% maturity, derived from previously published length-at-maturity estimates, was 17 years for males and 21 years for females. The results of this study agree with general life history traits already recognized for many Sebastes species, such as long life, slow growth, and late age at maturation. These traits may undermine the sustainability of blackgill rockfish populations when heavy fishing pressure, such as that which occurred in the 1980s, is applied.

Transportation of fish in India: problems and prospects

India has a long coast line of about 4,800 km along which fish landing centers are scattered. Fish catches are showing an upward trend consequent on rapid mechanization of fishing crafts. Economic utilization of the landed fish is an essential prerequisite for the proper development of Indian fishing and fish processing industries.

A report of the Fisheries Catch Assessment Survey in the Ugandan waters of Lake Victoria for the February 2008 survey

Between July 2005 and February 2008, ten Catch Assessment Surveys (CASs) were conducted at 54 pre-selected fish landing sites in the Ugandan part of Lake Victoria comprising approximately 10% of all landing sites in each of the 11 districts sharing the lake. The CASs were conducted following regionally harmonised Standard Operating Procedures (SOPs). This report covers the CAS conducted in February 2008 and puts into context the trends generated by results of the previous surveys. The catch rates of Nile perch in gillnetting boats with motor/sail, reduced from 26.9 kg boat-1 day-1 in August 2007 to 22.8 kg boat-1 day-1 in February 2008. Whereas the catch rates of paddle Sesse boats remained more or less the same as in August 2007. The Nile perch catch rates of the long line fishery of the boats using motor/sail was similar, 35 and 36 kg boat-1 day-1 in August 2007 and February 2008 respectively but the catch rates of paddle Sesse boats using long lines showed some more increase from 19 to 22 kg boat (-1) day (-1). In the tilapia fishery, the catch rates of the parachute boats using gillnets showed further decrease in a row from 12.6 kg boat-1 day-1 in December 2006, 11.6 kg boat-1 day-1 in March 2007, 11.2 kg boat-1 day-1 in August 2007 and 10.0 kg boat-1 day-1 in February 2008. The overall impact of reduced catch rates in the predominant effort groups, e.g. gillnetting boats using motor/sail in the Nile perch fishery and Parachute boats using gillnets in the tilapia fishery overshadowed the increases in less dominant effort groups and resulted in the lowest monthly catch estimates recorded in the surveys conducted since 2005. Whereas there was a clear downward trend in the Nile perch catch rates of boats using gillnets, which corroborates with the information of declining stocks from the recent Acoustics surveys, the catch rates in the long line fishery remained stable and even somewhat increasing in the last four surveys. The factors that maintain high catches against reduction of fish biomass in the long line fishery and their effects on sustainability of the Nile perch fishery should be investigated further. The Mukene fishery, characterised by large fluctuations in the catch rates did not show much change in the last two surveys in August 2007 and February 2008 and the annual catch estimates showed an overall increase of 7% from 2005 to 2007. The Mukene fishery in the Ugandan waters of Lake Victoria remained a near shore fishery in which paddle Sesse boats using small seines or scoop nets were the dominant craft.

Report of the Frame Survey of Lake Albert conducted in May 2012

Lake Albert and Albert Nile are a major source of fisheries resources sustaining the riparian communities in Uganda and the Democratic Republic of Congo (DRC). Like all shared bodies of Uganda Lake Albert and Albert Nile fisheries are faced with immense exploitation pressure one time described as the tragedy of the commons. In Uganda, the lake is shared by five riparian districts namely: Buliisa, Bundibugyo, Hoima, Kibaale and Nebbi. The lake covers a total estimated surface area of 5,270 square kilometers with approximately 60% within Ugandan waters. It is located in the western part of the great rift-valley at an altitude of 618 m above Sea level. The central parts of the lake are characterized by steep escarpments whereas the northern and southern parts lie in a plain of the rift valley. The plains are gently sloping, resulting in shallow swampy inshore waters in many places. The major inflowing rivers are the Semliki and Kafu in the south, and the Victoria Nile at the northern tip. The lake has a diverse fish fauna with a gradient of multi-species fisheries in different parts of the lake. The overall objective of the Frame Survey was to provide information on the facilities and services at landing sites and the composition, magnitude and distribution of fishing effort to guide development and management of the fisheries resources of Lake Albert and Albert Nile. The specific objectives were to provide information on: a) The number of fish landing sites; b) The facilities available at the fish landing sites to service the sector including accessibility; c) The service providers especially fisheries staff at fish landing sites; d) The number of fishers; e) The number and types of fishing crafts and their mode of propulsion; f) The number, types and sizes of fishing gears used on the lake and their mode of operation.

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.

National report of the frame survey 2010 on the Uganda side of Lake Victoria

This is a report on the results of the Frame Survey conducted in the Uganda side of Lake Victoria during August 2010 by the LVFO Institutions, namely: the Department of Fisheries Resources (DFR) Uganda and the National Fisheries Resources Research Institute (NaFIRRI) in close collaboration with the District Fisheries offices of Busia, Bugiri, Mayuge, Jinja, Mukono, Kampala, Wakiso, Mpigi, Masaka, Kalangala and Rakai. The authors are grateful to the LVEMP II, for providing funds for the survey and the LVFO secretariat coordination. Fisheries Frame surveys have been carried out on Lake Victoria biannually since 2000 to determine the number of fishers, fish landing sites, and facilities at the landing sites, as well as the composition of fishing crafts, their mode of propulsion, fishing gears and the fish species they target. This information is used to guide development and management of the lake’s fisheries. Following the reorganisation of landing sites into Beach Management Units (BMUs), the number of landing sites decreased from 597 in 2000 to 435 in 2008. The survey in 2010 showed an increase to 503 landing sites, an indication that new landing sites are coming up. The fish landing sites continue to have inadequate facilities such as fish shades, cold rooms to service the fisheries industry and very few (5%) have access to electricity and 32% had access to all weather roads. There has been some progressive improvement in the landing site coverage of basic hygiene and sanitation facilities, especially public toilet facilities from 17% in 2000 to 39% in 2010; and portable water from 4% to 17% respectively. However more effort is required to cover all landing sites. Most landing sites (83%) have access to mobile phone networks which eases communication. 46% of landing sites had access to a Health clinic and 64% had a Primary school within a radius of 2 km.

National report of the frame survey 2006 in the Ugandan part of Lake Victoria

Fisheries Frame surveys have been carried out on Lake Victoria biannually since 2000 to determine· the number of fishers, fish landing sites, facilities at the landing sites. Information on the composition fishing crafts, their mode of propulsion, fishing gears and the fish species they target is also collected. This information is used to guide development and management of the lake's fisheries. The results of the four surveys carried out since 2000 show that the number of landing sites has decreased by 24% from 597 in 2000 to 481 in 2006, mainly as result of reorganisation of landing sites into Beach Management Units (BMUs). The fish landing sites continue to have inadequate facilities to service the fisheries industry e.g. in the 2006 survey only 11.2% of landing sites had fish shades; <0.6% had cold rooms; 3.5% had electricity; and only 35.5% had toilet facilities. Similarly, only 11.4% of landing sites had portable water; 2.5% had jetties, 3.7% had 'fish stores; and 36% were accessible by all weather roads. There is need to improve facilities servicing fisheries at landing sites, with major emphasis on sanitary facilities, especially toilets and portable water. The BMUs should be sensitised to prioritise the construction and utilisation of public toilet facilities at their respective landing sites. The ultimate aim should be to have public toilets at all fish landing sites. The trend of the various indicators of fishing effort has continued upwards: The total number of fishers increased by 43.5% from 37,721 in 2004 to 54,148 in 2006 and the number of fishing crafts increased (43.9%) from 16,775 in 2004 to 24,148 in 2006 over the same period. The total number of gillnets increased by 28.6% from 458,597 in 2004 to 589,777 in 2006 and the number of long line hooks increased by 136% from 968,848 to 2,285,609. The number of fishing crafts using outboard engines also increased from 3,173 in 2004 to 5,047 in 2006 suggesting that more fishers were going far in search of fish. There is still a large number of illegal gears especially beach seines, which increased by 58.8% from 954 in 2004 to 1420 in 2006. Efforts to remove these very destructive gears should be stepped up. There was also larger increase in number of illegal gillnets <5 inch mesh size. These increased by 63% from 56,246 in 2004 to 91,740 in 2006 compared with 23.8% increase of gillnets ~5 inch mesh size. There were also large increases in the numbers of gillnets of 5 and 5% inch mesh size, which increased by 48% and 130% from 2004 to 2006 implying a trend towards use of smaller gillnet mesh sizes. The number of traps which are used in shallow vegetated areas, flood plains and river mouths to target tilapiines and riverine species decreased drastically from 5,361 traps in 2004 to only 499 traps in 2006, a decrease of 974%, a phenomenon attributed to the receding water levels which have left the shallow vegetated areas dry. A total of 17,475 fishing crafts, 72% of all fishing crafts, in the Ugandan part of the lake are still using paddles and the. number of parachute crafts is also still very high, (Le. 5,064) comprising a high proportion (21 %) of the total number of fishing. There is need to promote the use of large fishing crafts with sails or a combination of sail and outboard motor. The Mukene fishery in the Ugandan waters of Lake Victoria has remained underdeveloped with only 9% of all fishing crafts operating in this fishery. Also less than 2% of fishing crafts with sails or motor operate in this fishery which implies that it is limited to near shore waters. Effort should be made to develop this fishery as it appears to have high potential, especially in deep offshore waters which are hardly fished.

Technical report of frame and catch assessment surveys of Lakes Edward and George; and the Kazinga Channel conducted in January and July 2011- 2013

This study aimed at evaluating the production levels in terms of catch estimates of the artisanal fisheries of the Edward-George system in addition to providing information on the facilities and services at landing sites and the composition, magnitude and distribution of fishing effort to guide development and management of the fisheries resources of the Edward and George lakes and Kazinga channel. Specifically, the study was expected to come up with the following outputs:- a) Information on the number of fish landing sites on the basin lakes; b) Information on the facilities available at the fish landing sites to service the fisheries sector ; c) Information on the number of fishers; d) Information on the number and types of fishing crafts; e) Information on the modes of propulsion of the fishing crafts; f) Information on the number types and sizes of fishing gears including the number of illegal fishing gears in the fishery; and g) Recommendations on development and management of the fisheries of the Edward and George lakes and Kazinga channel. h) Beach values in terms of annual catches and annual revenue from the water bodies.

Sustainable livelihood approach of prawn production and marketing systems in Mymensingh, Bangladesh

An investigation was carried out in Phulpur upazila, Mymensingh to examine the current production practices of freshwater giant prawn, Macrobrachium rosenbergii and its marketing systems with sustainable livelihood approach. The livelihoods of a considerable number of rural poor are associated with prawn production in Phulpur upazila. Based on a sample of 50 farmers, about 94% farmers were found to culture prawn with fish in their ponds. Only 4% and 2% farmers were found to culture prawn-fish-dike crops and only prawn respectively. Prawn marketing is almost exclusively a preserve of the private sector where the livelihoods of a large number of people are associated with its distribution and marketing systems. The market chain from producers to consumers passes through a number of intermediaries. About 40% of the produced prawns are exported and the rest 60% are sold to local markets. The price of prawn depends on quality, size and weight. The average farm-gate price of prawn varied from Tk. 110 to 160/kg, whereas it's [sic] market price varied from Tk. 150 to 350/kg. Most of the farmers and traders have improved their socio-economic conditions through prawn farming and marketing activities. However, concerns arise about the long-term sustainability of prawn farming and marketing systems due to lack of technical knowledge of prawn farming, poor road and transport facilities, higher transport cost, poor supply of ice, lack of cash and credit facilities. It is therefore essential to provide institutional and organizational support and credit facilities for sustainable prawn production and marketing systems.

Implications of the industrial fish processing growth for the commercial fishery and fishers in Uganda

The study was undertaken to generate socio-economic information on fish market systems and performance of the industrial processing industry, which will guide the processes leading to modernization of the fisheries sector and, sustainability of Lake Victoria fisheries. The main objective of this study was to evaluate the socio-economic implications of the fish marketing systems with particular emphasis on fish export market in Uganda. The study thus, analysed the socio-economic characteristics of fishers and examinined fish marketing systems and the impacts on the fishing activities, food security, employment opportunities and incomes of fisher-folk communities.

The biology and ecology of the Nile perch, Lates niloticus, and the future of its fishery in Lakes Victoria, Kyoga and Nabugabo

Lakes Victoria, Kyoga and Nabugabo had a similar native fish fauna of high species diversity. stocks of most of the native species declined rapidly and some completely disappeared after Nile perch was introduced and became well established. Although, overexploitation of the fish stocks, competition between introduced and native tilapiines and environmental degradation contributed to the reduction in fish stocks, predation by the Nile perch has contributed much to the recent drastic reductions in fish stock and could even drive the stocks to a total collapse. Nile perch is also currently the most important commercial species in Lakes victoria, Kyoga and Nabugabo and the stability of its stocks is important in the overall sustainability of the fisheries of these lakes. The question that was to be examined in this paper was whether the fisheries of Lakes Victoria, Kyogaand Nabugabo would stabilize and sustain production in the presence of high predation pressure by the Nile perch or whether the Nile perch would drive the fish stocks including itself to a collapse. I t was assumed that Nile perch driven changes in Lakes Victoria, Kyoga and Nabugabo would be driven to a level beyond which they would not change further. This would be followed by recovery and stability or the changes would continue to a point of collapse. It was assumed that Lake Albert represented the ideal stable state. The changes in the new habitats expected to be driven through a major change due to Nile perch predation to a stage where there would be no further changes. After this, a feedback mechanism would move the driven variable towards recovery. The variables would then stabilize and oscillate will an amplitude which approximates to what would be recorded in Lake Albert. Alternatively, the changes would proceed to a stage where the fishery would collapse. The specific hypothesis was that fish species composition and diversity, prey selection by the Nile perch and life history characteristics of the Nile perch in the new habitats would change and stabilize

National report of the frame survey 2012 on the Uganda side of Lake Victoria

This is a report on the results of the Frame Survey conducted in the Uganda side of Lake Victoria during August 2012 by the LVFO Institutions, namely: the Department of Fisheries Resources (DFR) Uganda and the National Fisheries Resources Research Institute (NaFIRRI) in close collaboration with the District Fisheries offices of Busia, Bugiri, Namayingo, Mayuge, Jinja, Buvuma, Buikwe, Mukono, Kampala, Wakiso, Mpigi, Kalungu, Masaka, Kalangala and Rakai. In the 2012 Frame survey some indicators of fishing effort including e.g. number of fishers, fishing crafts and long line hooks increased; whereas others like the number of gillnets less than 5 inches decreased by 10.4% from that recorded in 2010. The other indicators of fishing effort, which showed decrease in 2012 included illegal beach seines and undersized gillnets (<5 inch mesh size). However, a large proportion (66%) of long line hooks recorded in the 2012 survey were in the smallest size range (hook size >10), which target small Nile perch. The number of other illegal gears, i.e. cast nets and monofilament gillnets showed modest increases (25%) between 2010 and 2012 while beach seines decrease by 15%. Recent crackdown on illegal fishing activities as part of measures for recovery of the Nile perch stocks which are faced with depletion appear to have had an impact but much more needs to be done to eradicate illegal fishing. The fisheries in the Ugandan waters have remained predominantly near shore with 61% of all fishing crafts using paddles out of which 17% were tiny three plank, flat bottomed boats locally known as parachutes. The 2012 survey shows an increase in the number of fishing crafts using sails by 65% from 682 in 2010 to 1125 in 2012. This is an encouraging trend as more fishers are able to access distant fishing grounds using free wind power. The Mukene fishery in the Ugandan waters of Lake Victoria remained underdeveloped comprising only 15.2% of all fishing crafts, of which 31% were motorised which is a great improvement from the situation recorded in 2010. The Catamarans increased to 18 with a majority in Buikwe district where there is a private investor fishing specifically for Mukene. The Catamarans in Kalangala were reported not to be working because of the high operating cost compared to ordinary Mukene fishing boats.