Experimental evaluation of influence of FADs on community structure and fisheries in coastal Kenya

Fish aggregating devices (FADs) have been widely used by commercial fisheries to increase the catchability of pelagic stocks in the open sea. FADs have the potential to enhance nearshore small-scale fisheries where stocks are often overfished. This study examined changes in catch composition, abundance, catch and effort, and aspects of diversity in Kenya's nearshore coastal fisheries after deployment of anchored fish aggregating devices (AFADs). The study combined both fishery independent and dependent methods in assessing changes in fish assemblages post-deployment. Results showed orders of magnitude increase in length, weight, commercial value, and catch per unit effort (CPUE) of landed catch after deployment of FADs suggesting that FADs had a positive effect on the local fishery. Species richness at FAD sites increased post-deployment (n = 281) compared to pre-deployment values (n = 223). Simultaneous use of several complementary structural indices may be required in order to accurately describe and monitor fish assemblages around the FADs. The findings suggest that AFADs are capable of creating both short and long-term impacts on livelihoods, with the potential to deflect pressure on the overfished nearshore fish stocks. However, more research will be needed on redistribution of fish around FADs, design and placement configuration, and site selection amongst others.

Download Full-text

Evaluating the suitability of fyke nets for small-scale fisheries in the Free State Province of South Africa

Water SA ◽

10.17159/wsa/2020.v46.i1.7895 ◽

2020 ◽

Vol 46 (1 January) ◽

Cited By ~ 1

Author(s):

LM Barkhuizen ◽

OLF Weyl

Keyword(s):

South Africa ◽

Clarias Gariepinus ◽

Total Sample ◽

Free State ◽

Small Scale ◽

Catch Per Unit Effort ◽

Free State Province ◽

Small Scale Fisheries ◽

Catch Composition ◽

Fyke Nets

South Africa is under increasing pressure to develop small-scale fisheries in inland waters. To inform appropriate development of this sector in the Free State Province, the catch rate of double-ended fyke nets was evaluated using survey data from 20 impoundments sampled during the 2013/2014 summer season. Fyke nets were set over night and the total sample effort was 114 fyke net nights. Overall catch per unit effort (CPUE) was 16.8 ± 28.3 kg·net-1·night-1 and catch composition was dependent on impoundment, but generally comprised of a mixture of common carp Cyprinus carpio, African sharptooth catfish Clarias gariepinus, smallmouth yellowfish Labeobarbus aeneus, Orange River mudfish Labeo capensis and moggel Labeo umbratus. The influence of temperature and the potential benefits of baiting the nets were subsequently evaluated through monthly sampling in the hyper-eutrophic Krugersdrift Dam and at the oligotrophic Gariep Dam. Baiting did not significantly influence CPUE, which was significantly higher at Krugersdrift Dam (19.97 ± 23.22 kg·net-1·night-1) than at Gariep Dam (5.02 ± 6.05 kg·net-1·night-1). Increasing temperature had a positive effect on CPUE at Krugersdrift Dam but not at Gariep Dam. Species composition also differed between impoundments and, as a result, we conclude that seasonal catch rates and species compositions will need to be evaluated prior to implementation of fyke net fisheries in specific localities.

Download Full-text

Catch per unit effort (CPUE) and catch composition of small scale fisheries in Gökova Bay

Ege Journal of Fisheries and Aquatic Sciences ◽

10.12714/egejfas.2015.32.3.03 ◽

2015 ◽

Vol 32 (3) ◽

pp. 135-143

Author(s):

Hakkı Dereli ◽

Zafer Tosunoğlu ◽

Huriye Göncüoğlu ◽

Vahdet Ünal

Keyword(s):

Small Scale ◽

Catch Per Unit Effort ◽

Small Scale Fisheries ◽

Unit Effort ◽

Catch Composition

Download Full-text

Strategies of the small-scale fisheries on the Central Amazon floodplain

Acta Amazonica ◽

10.1590/1809-43922002321108 ◽

2002 ◽

Vol 32 (1) ◽

pp. 101-108 ◽

Cited By ~ 2

Author(s):

Carlos Edwar de Carvalho FREITAS ◽

Vandick da Silva BATISTA ◽

Antonio José INHAMUNS

Keyword(s):

Hydrological Cycle ◽

Small Scale ◽

Good Tool ◽

Central Amazon ◽

Small Scale Fisheries ◽

Fisheries Resources ◽

Patterns Of Use ◽

Target Fish ◽

Catch Composition ◽

High Level

A multivariate approach was applied to data of small-scale fisheries developed in Central Amazon, using information about catch composition, environment, fishing gear and season of the hydrological cycle. The correspondence analysis demonstrated to be a good tool for the analysis related multispecies fisheries. The analysis identified patterns of use of fisheries resources by the riverine communities, showing the correlation between the environmental factors and the fishing strategy for the capture of target fish species, indicating the high level of empiric knowledge about the environment and fisheries.

Download Full-text

A Bio-Economic Analysis of the Liberian Coastal Fisheries

Sustainability ◽

10.3390/su12239848 ◽

2020 ◽

Vol 12 (23) ◽

pp. 9848

Author(s):

Alvin Slewion Jueseah ◽

Dadi Mar Kristofersson ◽

Tumi Tómasson ◽

Ogmundur Knutsson

Keyword(s):

New Technologies ◽

Fishing Effort ◽

Small Scale ◽

Exclusion Zone ◽

Coastal Fisheries ◽

Small Scale Fisheries ◽

Species Complexes ◽

Limited Enforcement ◽

Dugout Canoes ◽

The Government

Many coastal fisheries are subject to harvesting externalities due to inadequate regulations compounded by limited enforcement. Coastal fisheries in Liberia consist of a fleet of dugout canoes (Kru) primarily targeting demersal finfish, larger open wooden boats propelled with outboard engines targeting small inshore pelagics (Fanti), and a small number of industrial trawlers employing midwater and bottom trawls targeting finfish and shrimp. This paper develops a bio-economic model for the coastal fisheries in Liberia and employs the model to identify economic optimal fishing effort and harvesting trajectories for the different coastal fleets. The results show under harvesting and disinvestments in the coastal fisheries in Liberia. In 2010 the Government of Liberia declared a six nautical mile inshore exclusion zone accessible only to small-scale fisheries (SSF), which was accompanied by increased enforcement. The coastal fleets in 2016 were profitable but the distribution of profits was tilted to the small-scale fleets. The government needs to evaluate what policy options are available to fully utilize the fisheries potential for different species complexes while at the same time reduce the risk of conflict and overharvesting. There appears to be a need for investment in new technologies, which can only take place if fishing in Liberia will remain profitable.

Download Full-text

A spatial multivariate approach to understand what controls species catch composition in small-scale fisheries

Fisheries Research ◽

10.1016/j.fishres.2015.11.028 ◽

2016 ◽

Vol 175 ◽

pp. 132-141 ◽

Cited By ~ 10

Author(s):

M. Grazia Pennino ◽

Mario J.F. Thomé-Souza ◽

Adriana R. Carvalho ◽

Luiz Carlos da Silveira Fontes ◽

Cristiano Parente ◽

...

Keyword(s):

Small Scale ◽

Multivariate Approach ◽

Small Scale Fisheries ◽

Catch Composition

Download Full-text

OVERFISHING AND OVERCAPACITY SMALL SCALE FISHERIES IN SEMARANG CITY

Jurnal Ilmu dan Teknologi Kelautan Tropis ◽

10.29244/jitkt.v11i2.24817 ◽

2019 ◽

Vol 11 (2) ◽

pp. 427-435

Author(s):

Jamaludin Malik ◽

Achmad Fahrudin ◽

Dietriech Geoffrey Bengen ◽

Taryono Khodiron

Keyword(s):

Sustainable Management ◽

Maximum Sustainable Yield ◽

Utilization Rate ◽

Small Scale ◽

Fishing Gear ◽

Catch Per Unit Effort ◽

Small Scale Fisheries ◽

Surplus Production ◽

Capacity Level ◽

The Status

Fisheries in Semarang City are dominated by small-scale fisheries. This is indicated by the use of the largest fishing fleet of 10 gross tons operating near the coast. This study aims to analyze the status of small-scale fisheries in Semarang City for sustainable management. Sustainable management is management that guarantees the availability of natural resources and environmental services for future generations. The study was conducted for three months, namely September-November 2018 in the coastal waters of Semarang City, which was part of the Fisheries Management Region (WPP) 712. The method used in this study is the analysis of time series surplus production, namely data from the catch (ton/year) and the number of fishing gear (unit) within 10 years (2007-2016), to calculate the catch per-unit effort (CPUE), maximum sustainable yield (MSY), optimum effort (fopt), utilization rate (TP) and capacity level (TK). This study was obtained results of a downward trend in CPUE; the existing fishery catch or production in 2016 has exceeded the MSY value is 479 tons/year (Schaefer) and 439.11 tons/year (Fox); utilization rate of more than 100% which is 108-127% (Schaefer) and 118-138% (Fox), so that small-scale fisheries in Semarang City are at the level of over-exploited. Based on the fopt analysis, the number of fishing gear used (fexisting) has exceeded the optimum effort with a fishing capacity exceeding 100%, so that small-scale fisheries in Semarang City have experienced overcapacity.

Download Full-text

Fishing Effort and Associated Catch per Unit Effort for Small-Scale Fisheries in the Mozambique Channel Region: 1950–2016

Frontiers in Marine Science ◽

10.3389/fmars.2021.707999 ◽

2021 ◽

Vol 8 ◽

Author(s):

Dirk Zeller ◽

Gabriel M. S. Vianna ◽

Matthew Ansell ◽

Angie Coulter ◽

Brittany Derrick ◽

...

Keyword(s):

Fishing Effort ◽

Small Scale ◽

Catch Per Unit Effort ◽

Important Species ◽

Small Scale Fisheries ◽

Mozambique Channel ◽

Fishing Vessels ◽

Unit Effort ◽

Fishing Capacity ◽

Channel Region

The Mozambique Channel region in East Africa has diverse marine ecosystems and serves as a migratory corridor for economically important species. Local and foreign industrial fisheries operate in the Mozambique Channel, but regional small-scale fisheries are the crucially important fisheries that provide food security, livelihoods, and economic opportunities for rural coastal communities. This study reconstructed and investigated trends in the fishing effort and catch per unit effort (CPUE) of small-scale marine fisheries in four Exclusive Economic Zones (EEZ) that constitute the Mozambique Channel, i.e., Union of Comoros, Madagascar, Mayotte, and Mozambique, from 1950 to 2016. Effective fishing effort for small-scale fisheries in the form of fishing capacity in kWdays (i.e., kilowatt days) was derived using the number, length, motorization (engine power) by fishing vessels, as well as an approximate human-powered equivalent for shore-based fishers without vessels, as well as days of fishing per year. Effective small-scale fishing effort in the Mozambique Channel increased by nearly 60 times from just over 386,000 kWdays in 1950 to over 23 million kWdays in 2016. Correspondingly, the overall small-scale CPUE, based on previously and independently reconstructed catch data declined by 91% in the region as a whole, from just under 175 kg⋅kWday–1 in the early 1950s to just over 15 kg⋅kWday–1 in recent years. All four EEZs showed the strongest declines in the small-scale CPUE in the earlier decades, driven by motorization and growth in vessel numbers impacting effective fishing effort. Increased motorization combined with a substantial growth in overall vessel numbers were the drivers of the increasing fishing effort and decreasing CPUE, and clearly suggest that continuing to increase the fishing capacity of small-scale fisheries in the absence of effective and restrictive management actions may exacerbate overexploitation risk.

Download Full-text

Impacts of small-scale fisheries on mangrove fish assemblages

ICES Journal of Marine Science ◽

10.1093/icesjms/fsy110 ◽

2018 ◽

Vol 76 (1) ◽

pp. 153-164 ◽

Cited By ~ 4

Author(s):

José Amorim Reis-Filho ◽

Euan S Harvey ◽

Tommaso Giarrizzo

Keyword(s):

Species Richness ◽

Fishery Management ◽

Management Practices ◽

Fish Assemblages ◽

Small Scale ◽

Fishing Pressure ◽

Community Size ◽

Small Scale Fisheries ◽

Fishing Impacts ◽

The Impact

Abstract The data requirements and resources needed to develop effective indicators of fishing impacts on target stocks may often be great, especially for mangrove fisheries where, for example, tidal cycles sequentially flood and drain the habitat as a result of natural processes. Here, we used underwater video systems to evaluate the impact of small-scale fisheries on mangrove fish assemblages at four levels of fishing pressure (low, medium, high, and no pressure). The lowest values of species richness and abundance were recorded in the areas fished most intensively. Conversely, the highest species richness and the occurrence of larger-bodied fish were recorded in areas of reduced fishing activity, which was surprisingly similar to the “no fishing” areas. The slopes of the community size spectra steepened in response to exploitation, while the relative abundance of medium-sized fish (16–25 cm) declined. Fishing for local or regional markets, rather than subsistence, also led to a decrease in the abundance of larger fish (>41 cm). The marked response of population parameters to fishing pressure reflected the impact of unregulated small-scale fisheries on areas of mangroves. Fishery management practices that ignore contemporary changes in these environments are likely to overestimate long-term yields, leading to overfishing. Thus, size-based approaches to evaluating fishing pressure were suitable for detecting negative responses from the mangrove fish assemblages. A next step will be to integrate size- and species-based ecological approaches that provide mechanisms to address pronounced decreases in specific species as a more profitable indicator of fishing impacts on mangrove fish assemblages. This approach will allow the development of effective conservation and management strategies.

Download Full-text

Small-scale fisheries in Madeira: recreational vs artisanal fisheries

Scientia Marina ◽

10.3989/scimar.05180.022 ◽

2021 ◽

Vol 85 (4) ◽

pp. 257-270

Author(s):

Roi Martínez-Escauriaza ◽

Francesca Gizzi ◽

Lídia Gouveia ◽

Nuno Gouveia ◽

Margarida Hermida

Keyword(s):

Coastal Ecosystems ◽

Small Scale ◽

Artisanal Fisheries ◽

Artisanal Fishery ◽

Catch Per Unit Effort ◽

Small Scale Fisheries ◽

Recreational Fishery ◽

Management Of Resources ◽

Pagrus Pagrus ◽

Phycis Phycis

Small-scale recreational and artisanal fisheries are popular activities in the Autonomous Region of Madeira, and to date no information is available on their impact on regional coastal ecosystems. Through fishers’ surveys and official registers of fish landings, we described and characterized these fisheries in Madeira, comparing artisanal and recreational fisheries. In 2017, artisanal boats landed 91 species in fishing ports, while recreational catches landed 58 species. The most frequent catches were Dentex gibbosus, Phycis phycis and Pagrus pagrus for artisanal fishery and P. pagrus, Serranus atricauda and Diplodus spp. for recreational fishery. Comparing the same techniques, artisanal fishery always showed higher catch per unit effort values than recreational boat fishery. Nevertheless, the low number of artisanal fishery boats in comparison with the recreational ones reflected the lower total landings of the artisanal fishery, which in 2017 were 62.3 t, compared with the 509.8 t estimated catches for the recreational fishery. Though the estimated recreational fishing data were based on surveys and thus subject to various biases, this activity seems to negatively affect coastal ecosystems and, together with artisanal fishing, exerts a combined pressure on targeted species. Improved legislation for both fisheries is essential for an appropriate management of resources.

Download Full-text

SEASONAL AND SPATIAL DYNAMIC OF SMALL SCALE FISHERIES IN CENTRAL AMAZONIA

Terceira Margem Amazônia ◽

10.36882/2525-4812.2020v6i15p206-223 ◽

2021 ◽

Vol 6 (15) ◽

pp. 206-223

Author(s):

Vinícius Verona Carvalho Gonçalves ◽

Jamerson Aguiar Dos Santos ◽

Carlos Edwar de Carvalho Freitas

Keyword(s):

Local Population ◽

Principal Component ◽

High Water ◽

Small Scale ◽

Catch Per Unit Effort ◽

Fishing Activity ◽

Small Scale Fisheries ◽

Central Amazonia ◽

Flood Period

Amazonia is considered to host some of the more productive freshwater fisheries of the world, and these are of key importance to the local population. Accordingly, fishing activity needs to be studied to evaluate its dynamics, so that long-term sustainability of the resource can be assured the fishing. The objective of the current study, therefore, was to analyze seasonal and spatial variation in the production of fish landed in the city of Manacapuru, in Central Amazonia. The landing data was collected daily from January to December 2012 at the main port of landing in Manacapuru, Amazonas, Brazil. Results indicate that lakes were most frequently visited by fishermen, but that rivers had higher catch values. In total, 39 species of fish were landed, with jaraqui escama grossa (Semaprochilodus taenirus) and jaraqui escama fina (Semaprochilodus insignis) being the species most exploited by fishermen. Landing had a seasonal character, with higher values in the rising and high water periods. Significant differences were observed between the different seasonal periods, with peak-flood period having the highest catch per unit effort (CPUE) values. Principal Component Analysis (PCA) revealed that fishing gear varied according to the fishing environment and exploited species.

Download Full-text