Declining Fish Catches Research Articles

Effects of Decline in Fish Landings on the Livelihoods of Coastal Communities in Central Region of Ghana

Fishing along Ghana’s coast is the main livelihood for local communities, and it contributes significantly to their incomes. Most of them get employment, food security, and access to better health care through fishing activities. However, the fishing industry has been saddled with many challenges in recent times, which has led to low landings. This study aimed to assess the causes and effects of the decline in fish landings on the livelihood of coastal communities in the Central Region of Ghana. The systematic sampling technique was used to randomly select 200 households from four communities. A questionnaire was designed to elicit information from fisherfolk based on Likert scale estimation. In addition, time-series data of fish landings and imports for 51 years (1976–2017) was used in the analysis. The results from the study indicate that fish landings are declining, and this is affecting the income levels of fisherfolk. However, the impact of income decline on the female fisherfolk is lower as compared to their male counterparts. To mitigate against dwindling incomes, the fisherfolk have adopted livelihood diversification coping strategies. The key livelihood options identified in the communities are masonry, trading, and commercial driving. The fisherfolk mentioned overfishing, pollution, use of smaller mesh size nets, and unapproved methods of fishing as drivers of decline in fish landings. This study recommends that mandated institutions with oversight responsibilities in the fishing industry should be strengthened to enable them to conduct their functions effectively, so, they halt the decline in fish catch.

Is the closed fishing season policy effective in curbing catch declines?

Executive Summary. The closed fishing season policy is annually imposed in Davao Gulf to allow the fish stocks to recover and address the declining fish catch. Whether the closed season is effective in reducing catch and effort however, is still not determined. An assessment on the closed fishing season included survey and focus groups in Governor Generoso, Lupon, Davao City, Sta. Maria, Don Marcelino and Malita, as well as catch assessments using data from Philippine Statistics Office (PhilStat), and GPS tracking of willing small-scale fishers. A survey and an in-depth interview was also conducted to determined impacts on the fisheries market chain. Results of the study show that multiple factors contributed to the successful implementation of the closed fishing season in the Davao Gulf. Catch data analyses show that small scale fish catches have increased (municipal fishers) compared to commercial fish catches. Together the results show that the closed fishing season was effective in curbing catch declines for the fisheries. Thus, continuing the implementation of the closed season will contribute to the sustainability of fish stocks in the Davao Gulf. However, providing support and temporary jobs to displaced commercial fishers are needed.

Seasonal dynamics in fish distribution and abundance revealed by an acoustic survey in coastal waters of the Suzu Area, Kochi Prefecture, Japan

For Japan's fishery, it is essential to conduct sustainable and efficient fishery owing to the decline in fish catch as well as the fisher population. To obtain information that contributes to sustainable and efficient fishery, we researched appropriate set-net locations with regard to fish distribution, abundance, and environmental characteristics. We conducted surveys from 2017/5 to 2018/2 in the Suzu coastal area, Kochi Prefecture, where the only main industry is set-net fishery. We investigated the seasonal relationships between fish school characteristics, including distribution and size, and marine environmental conditions in the Suzu coastal area, using a quantitative echo sounder (KSE300 SONIC, 38 kHz) and other devices. We observed that every season showed similar trends in the horizontal structure; fish densities were higher on the coast side, and in some seasons, these were higher at approximately 2000 m offshore. In addition, fish densities were higher in seas at depths up to 30 m. Set-net fishery is conducted in Suzu District at 300 m from the shoreand at a depth of approximately 35 m. The point of installation of set-nets is based on fish school distribution. In our study, we determined the most appropriate set-net installation points. This study not only provides a scientific basis for point selection but could also enhance the existing fishery that is limited to an aging fisher population and catch instability.

Factors influencing catch and support for the implementation of the closed fishing season in Davao Gulf, Philippines

The closed fishing season policy is annually imposed in Davao Gulf to allow the fish stocks to recover and address the declining fish catch. Up to now, there were no assessments conducted to determine multiple factors that could have been contributing to its proper implementation in the Davao Gulf. A mixed-methods approach was used through interviews of fishers (N = 229) and supplemented by nine focus groups in Governor Generoso, Lupon, Davao City, Sta. Maria, Don Marcelino and Malita. Results of the regression analysis showed that the catch per unit effort (CPUE) was highly influenced by revenue and number of years of fishing experience (df = 3, MS = 7.38, F = 47.90, p < .001). In addition, the main predictors for the support of the imposition of closed fishing season were the number of fishing hours, fish price, membership to community organizations, and awareness of policy among fishers. Economic motivation seems to predominate among fishers as both factors: revenue and fish price, are related and increase due to the imposition of the closed fishing season. The fishing experience and the number of hours of fishing can both determine the catch success of fishers in their fishing grounds. In addition, the flow of information between fishers is usually done through membership with community organizations due to the familiarity of members with one another. Moreover, fisher to fisher interactions also help transmit information in the fishing grounds. Ultimately, the fisher's willingness to cooperate and support the closed fishing season policy will help determine the fish stocks recovery.

Factors Driving Long Term Declines in Inland Fishery Yields in the Mekong Delta

The Mekong basin’s fisheries are important sources of food, income, and livelihoods for millions of people in six countries. However, fish yields appear to have declined in recent years according to reports from local fishers throughout the basin. It is important to understand the factors driving the decline in fisheries so that they can be adequately managed. We analysed interview data from 1020 fishers in the Mekong Delta in Vietnam in 2014 to identify trends in catch rates and the possible factors driving the trends. Most of the fishers (68–90%) reported that their catch rates had declined over the previous five years, although some fishers stated that their fish catches had remained stable or even increased. They identified eleven factors that they believed contribute to declines in fish catches, among which the use of illegal gears and overfishing were considered most important, with other factors relatively unimportant. Separately, long-term datasets (1995–2016) showed a general decline in commercial fish catches, which was positively correlated with peak water levels (which indicate flood levels), and negatively correlated with the intensification of rice farming, especially where flooding has been prevented to allow a third annual rice crop. Some data suggests that fishing effort has declined significantly in recent years, so an apparent downward trend in catches is not likely to be a result of overfishing as believed by fishers, which suggests that fishers are not aware of or under-rate the significance of hydrological and land-use/landscape changes. Due to the exceptional importance of the Mekong fishery and the interactions with other more dominant sectors, improved data collection is required to quantify changes in fisheries that result from land use and hydrological changes, and to guide planning which would better resolve competing demands for water and land use.

Livelihood impacts and adaptation in fishing practices as a response to recent climatic changes in the upwelling region of the East African Coastal Current

A socio-economic assessment was carried out at Amu and Shela in Lamu County and Ngomeni in Kilifi County on the coast of Kenya. The aim was to establish fisher perspectives on the livelihood impacts of changes in upwelling associated with the East African Coastal Current, and adaptations in fishing practices to determine the vulnerability, resilience and adaptation options for fisheries dependent communities in this upwelling region. Primary data and information were collected through direct observation, semi-structured interviews, key informant interviews and oral histories. Descriptive and non-parametric analysis was conducted for quantitative data and content analysis for qualitative data. The study covered 92 respondents out of which 90 were male. About 82.5 percent of the respondents had attained different levels of primary school education and below, and were therefore highly vulnerable to climate change impacts. Furthermore, 80.4 percent of the respondents were aged between 20 years and 49 years with a mean age of 40 years, thus falling into the economically active age category. In terms of livelihoods, fishing and fishing-related activities formed the primary livelihoods at the three study sites with fishing being the main occupation for 93 percent of the respondents. Fishing effort was higher during the north-east monsoon season. Fifty two percent of the respondents targeted small pelagic species. The main changes observed included increased fishing effort and a decline in the quantity of fish caught per fisher, and changes in the composition of fish species. Changes in the composition of fish species have further been compounded by a decline in rainfall over time, sea level rise, irregular wind patterns and increased temperatures. The decline in fish catch further led to a general decline in income and welfare. The climatic changes increased vulnerability of the fishing communities.

Factors Contributing for Vulnerability on Livelihood of Fishers of Ratnagiri, Maharashtra State, India

Aims: The present study was carried out to investigate the impact of vulnerability on livelihood of fishers of Ratnagiri, Maharashtra state of India.&#x0D; Study Design: For this study interview schedule was used to collect the fisher information.&#x0D; Place and Duration of Study: In present study, the data were collected from the fishers of the three fishing villages of Ratnagiri district of Maharashtra during the year 2019-2020.&#x0D; Methodology: The data were randomly collected from 64 fisher by using questionnaire in the Google form and interview schedule. The vulnerability variables considered in this study are categorised as natural shocks like cyclones, heavy rain, environmental changes; personal factors like illness, sea accidents, sudden death, social conflicts and seasonality includes decline in fish catches, unpredictable price fall and non-availability of markets. The opinions of respondents with respect to vulnerability factors were recorded on the basis of three categories i.e. high impact, medium impact and low impact. The descriptive statistics i.e. percentage and frequency analysis was used to represent the results.&#x0D; Results: The overall results of vulnerability indicated that the natural shocks factors like cyclones, heavy rain, environmental changes and personal factors like illness, sea accidents, sudden death, social conflicts have high impact on more than 90% respondents; while seasonality factors like decline in fish catches, unpredictable price fall and non-availability of markets have high impact on livelihood of about 70% fishers respondents.&#x0D; Conclusion: The respondents reported that the various factors of vulnerability have direct impact on livelihood of fishers and ultimately socioeconomic conditions of the fishers.

The challenges experienced by small-scale fishing communities of Lake Kariba, Zimbabwe

Small-scale fisheries play a significant role in enhancing livelihoods, creating employment and contributing to food security especially in developing countries. Rural fishing communities are highly dependent on natural resources, which are climate sensitive. Many research efforts have been made to understand the impacts of climate change on fisheries and fishing economies. However, little attention has been given to understand the challenges experienced by small-scale fishing communities in developing countries in Africa. This article assesses non-climate change and climate change-induced challenges according to the experiences of the gillnet small-scale fishers of Sanyathi fishing basin of Lake Kariba, Zimbabwe. The study used a qualitative research design, and data were collected using semi-structured in-depth interviews with fishers. Thematic content analysis was used to analyse interview transcripts. The study results showed that declining fish catches is one of the major challenges experienced by fishers. The main themes that emanated as the challenges faced by fishers are food insecurity, wildlife attacks, lack of access to information systems, lack of fishing equipment, the existence of the predator crayfish, poor lake co-management and shrinking fishing boundaries. Overall, the study found that fish production is negatively affected by several political, economic and environmental factors; therefore, development through the public and private organisations should incorporate small-scale fishers in policy formulation to positively enhance livelihoods and food security.

Adaptive capacity and coping strategies of small-scale coastal fisheries to declining fish catches: Insights from Tanzanian communities

Small-scale fishing communities are expected to adapt to fish catch fluctuations linked to global environmental change. Notwithstanding, impacts from severe climate events and overexploitation of fisheries resources can compromise functions and resilience of ecosystems and associated species, and thereby jeopardize long-term population trend stability and fisheries productivity. To date, most assessments and vulnerability studies of fisheries-dependent populaces have focused on global, regional and national levels, while studies at village and community levels, where adaptive planning in the context of climate- and environmental changes is important, are less common. Based on data from official fishery records over a three-decadal period (1984–2016) and recent interviews with artisanal fishermen (319 fishers from eight communities) along the Tanzanian coast, we assessed small-scale fisheries with regard to (i) long-term trends in fishery landings, (ii) long-term alterations in fishing gear use, and (iii) fishers’ perceptions on how they have been coping and adapting to fluctuating fish landings. We further investigated (iv) the adaptive capacity of a wide range of coastal villages by assessing the fishers’ responses to an anticipated future scenario of a major (50 %) decline in landings from the current fisheries catch levels. The long-term trend records of fish landings showed a remarkable ∼50 % reduction in terms of both catch per vessel and catch per fisher from 1984 to 2016. According to the interviews, the majority of fishers (75 %) have changed fishing grounds from nearshore to offshore areas during the last decade, owing to a general perception that nearshore areas have suffered major reduction in fish stocks (due to overfishing and environmental changes related to extreme climate- or weather events), while offshore areas were considered still productive. The change in location of fishing grounds is probably a result of the clear switch in major gear type utilization from beach seine to ring net that occurred over the last decades. With a further progressive decline in fishery catches to a predictive level of 50 % of the current catch level, there is a general perception that artisanal fishers will continue fishing because alternative livelihoods (like crop farming, which employs more than 65 % of the population) have suffered similar negative impact. These findings highlight the need for building adaptive capacity in local coastal communities to develop alternative coping strategies for the impacts of climate- and environmental changes.

Can fishing communities escape marginalisation? Comparing overfishing, environmental pressures and adaptation in Thailand and the Philippines

In this article, we compare four fishing‐based areas in Thailand and the Philippines to examine if and how small‐scale fishing communities are able to escape marginalisation. Three questions guide our inquiry: (i) How have fishing communities been affected by overfishing, climate change and other pressures? (ii) What adaptive strategies have these communities employed to mitigate socio‐economic and environmental challenges? (iii) What has been the impact of these strategies on (escaping) marginalisation? Through a survey of 393 fishing‐based households and semi‐structured interviews with 59 key informants we find an uneven mixture of drivers, strategies and impacts. Respondents varyingly attribute declining fish catch to illegal fishing, overfishing, population increase, climate change and pollution. The case studies illustrate various degrees of adaptive successes that result from integration of top‐down and bottom‐up initiatives, and availability and access to livelihood strategies. However, the impact of adaptive strategies on overcoming marginalisation remains meagre and constrained by, among others, the power of illegal and commercial fishing and the absence of integrated spatial planning. We call for policy interventions and further research that takes into account the integration of top‐down and bottom‐up institutions, and the multiple dimensions and spaces of the drivers that shape fisherfolk marginalisation.

Effects of black soldier fly (Hermetia illucens L.) larvae meal on growth performance, organs-somatic indices, body composition, and hemato-biochemical variables of European sea bass, Dicentrarchus labrax

Fishmeal (FM) is one of the major protein sources used in fish diets, which was obtained from wild fish catches. Due to the steady decline in fish catches accompanied with the increased demands for aquafeeds, a rapid decrease in the FM availability is much more expected. Alternative protein sources of animal origins, such as dried black soldier fly (Hermetia illucens L.) larvae meal (DBSFLM), may be used as an alternative protein source instead of FM in aquafeeds. Therefore, a feeding trial was carried out to evaluate the effects of partial replacement of FM with DBSFLM on growth performance and body composition of European sea bass, Dicentrarchus labrax. A basal diet (45% crude protein) was formulated, where DBSFLM protein replaced 25, 35, or 50% of FM protein. Fish (12.1 ± 0.21 g) were fed one of the tested diets up to apparent satiation thrice a day for 8 weeks. No significant differences were observed in fish growth, feed utilization, and survival (P > .05). The DBSFLM inclusion in diets of European sea bass did not affect its body constituents. Additionally, values of red blood cells, hemoglobin, hematocrit, mean corpuscular volume, and mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration were not significantly influenced by DBSFLM inclusion in fish diets as compared to the FM-control fish. Likewise, no significant changes were observed in counts of white blood cells, lymphocytes, monocytes, and neutrophils in DBSFLM-fed fish as compared to the FM-control fish. The DBSFLM inclusion in diets for European sea bass did not affect levels of serum total protein, albumin, globulin, serum alanine aminotransferase, and aspartate aminotransferase. The simple economic analysis evoked that feed cost decreased with increasing DBSFLM levels in fish diets. The findings of the present study elucidated that the growth performance was not significantly changed by partial replacement of FM protein up to 50% by DBSFLM protein, which reduced the feeding cost by 15.6% as compared with the FM-control diet.

Fisherfolks’ Willingness-to-Pay for the Conservation of Atulayan Bay Marine Protected Area in Sagñay, Camarines Sur, Philippines

The Atulayan Bay is one of the established Marine Protected Areas in the Philippines in 1993 by virtue of Municipal Ordinance No. 93-001. Use of illegal fishing method and declining fish catch were the problems identified in the area. This study estimated the value of the benefits in conserving the marine resources in Atulayan Bay Marine Protected Area in Sagñay. The survey was conducted on February-March 2019 with 110 Atulayan and 225 Nato fisherfolks. The willingness to pay of the fisherfolks was estimated using the contingent valuation method. The parametric (logit regression) and non-parametric (turnbull) estimation were used to calculate for their willingness to pay to conserve the Atulayan Bay MPA. The estimated average willingness to pay per month of fisherfolk for the parametric estimation of Atulayan and Nato were PhP* 91 (US$1.72) and PhP 179 (US$3.39), respectively, and for the non-parametric estimation, PhP 86 (US$1.63) for Atulayan and PhP 27 (US$0.51) for Nato. The significant factors affecting the willingness to pay of Atulayan fisherfolks were income and bid level while for the Nato fisherfolks were age, income and bid level. The estimated willingness to pay values are a useful basis for the possible amount of tax that will be collected monthly from the registered fisherfolks by the municipal office for the conservation of the Atulayan Bay Marine Protected Area.

The current state of fish market in Ukraine

The fishing industry is an important component of the economy of Ukraine at the present stage of development. The development and implementation of the innovative technologies in fish farming and fish processing require mandatory and ongoing analysis of a fish market infrastructure. The demand for food protein, which is characterized by a balanced amino acid content is provided by fish and seafood at 20–30 %. The aim of this work was to understand a current state of a fish products market in Ukraine, its pricing and consumption. Based on the specialized literature the evaluation of a current state of fish and fish products consumption in Ukraine and own studies of the price category of fish products in Ukraine in recent years were conducted. We studied fish and fish products consumption per year per capita in Ukraine over the last 20 years, assortment of fish in Ukraine, the import of fish and fishery products by species, the product prices in UAH per kg both in previous years and today. According to international medical standards the annual consumption of fish and seafood should be 20 kg per person. At the same time in Ukraine according to the State Statistics Committee on the 01.01.2019 14.5 kg of fish and seafood came out per capita. In 2018–2019 herring traditionally remained a leader of consumption in Ukraine. Ukraine also imported such species of fish: mackerel, hake, herring, salmon, pilchards, pollack, capelin, sardines, notating. In addition pangasius, shrimp, blue whiting, mussels, squid, saury, Jack mackerel, sea bass, tuna, flounder, anchovies, smelt, cod, salmon and other species of fish, caviar and seafood are imported in Ukraine. The investigated assortment of fish in Ukraine is represented both domestic and imported products. The domestic production are: carp, pike, capelin, herring, mackerel, sprat, the imported products are: flounder, perch, pangasius, salmon, butter, hake, Pollock, capelin, nototenia, herring, mackerel, cod, tuna, tilapia (sole), sea trout, whiting and so forth. It is established that the condition of a fish market in Ukraine is affected by an unstable economic and political situation in the country, low solvency of the population, corruption and the high payables of the enterprises. In Ukraine a tendency towards a decrease in the volume of fish and fish products consumption by the population of Ukraine is observed annually, which is a consequence of the decline in fish catch and fish production, depreciation of fixed assets and a lack of financial support to the fishing industry.

The Impacts of Climate Change on the Livelihood and Food Security of Small-Scale Fishers in Lake Kariba, Zimbabwe

Small-scale fisheries play a significant role as a source of employment, livelihood strategy and contributor to food security. However, changes in climatic variables alter the productivity and distribution of marine and freshwater fish species, negatively affecting the livelihoods of fishery-dependent communities. This study seeks to identify small-scale fishers’ livelihoods and examine the impacts of climate change on livelihoods and food security of small-scale fishing households. The study was conducted in Sanyathi fishing basin in Lake Kariba, Zimbabwe. The Sustainable Livelihood Approach framework of the Department for International Development was used to define the small-scale fishers’ livelihood assets and activities. The study employed a mixed-method approach for data collection. A pretested, semi-structured questionnaire, focus group discussions and observations were used to collect data from the small-scale fishers. The data collected were subjected to descriptive and bivariate analysis. The present results indicate that fishing is the community’s primary livelihood activity. More than 62% of fishermen stated that fishing revenue is declining, owing to declining fish catches. Of participants, 98% recognised food purchases as the primary source of food. Therefore, 78% of the small-scale fishers perceive their households to be food insecure due to declining incomes from fisheries. These findings show the need for policymakers and development agencies to formulate strategies that specifically target fishing communities whose livelihoods rely on natural ecosystems.

Livelihood Strategy of Lake Fishing Community in Guguk Malalo Village, West Sumatra Province, Indonesia

Lake Singkarak is a livelihood source for people who live on the banks, especially for fishing activities. Unfortunately, this fishing sector shows a decline in fish catches since 1996 and significantly in 2007-2016. This paper presents the results of a study that specifically reveals the current state of the biophysical and environmental conditions of Lake Singkarak and explores the types of fishermen's livelihood strategies in relation to access to their livelihood assets at the current biophysical and environmental conditions of Lake Singkarak. This research framework adopts the Sustainable Livelihood Framework by applying a calculation of the index value/ratio of each livelihood asset. The results of this study indicate that changes in the biophysical conditions and the environment of the lake have played a role in influencing access to fishermen's livelihood assets at the study site and have implications for decreasing sources of livelihood from the lake. It was found that presently there are 6 types of livelihood strategies that are carried out by fishermen to be able to fulfill their living needs, namely Type B: Fishermen who carry out fisheries intensification and extensification (6.12%), Type C: Fishermen who have diversified their economic activities either in agriculture or non-agriculture (34.69%) , Type E: Fishermen who carry out fisheries intensification and extensification and also diversification (44.9%), Type F: Fishermen who carry out intensification and extensification of fishing and also temporary migration (2.04%), Type G: Fishermen who diversified their economic activities also temporary migration (4, 08%) and Type H: Fishermen who carry out fishing intensification/extensification, diversification and also temporary migration (8.16%). In relation to access to livelihood assets, it turns out that human resource assets are the main assets that influence the alternative choices of fishermen's livelihood strategies. The alternative type of strategy for diversifying economic enterprises, both in agriculture and non-agriculture, is the most widely chosen option besides alternative intensification and extensification of fishing in lakes.

Small-scale fishers’ perceptions of climate change and its consequences on fisheries: the case of Sanyathi fishing basin, Lake Kariba, Zimbabwe

Small-scale fisheries, especially in developing countries, are susceptible to the negative impacts of climate change. Changing climate is one of the factors altering fish productivity, resulting in declining fish catches. Studies have been done to investigate the nature and extent of these impacts. However, research indicates that fishers in developing countries are unaware of the climate change phenomena. Therefore, it is crucial to understand how small-scale fishers perceive climate change at a local level. This study presents small-scale fishers’ perceptions of climate change and further elucidates on the impacts of climate change on fish production in Sanyathi fishing basin, Lake Kariba, Zimbabwe. Mixed method research approaches were employed in the study. Semi-structured questionnaires were administered to 66 fishers. Meteorological time series data were used to triangulate the fishers’ perceptions of climate change. Cross-tabulations (chi-square tests) and descriptive statistics were used to analyse the data. Results indicated that 92% of the fishers are aware of climate change. There is a significant (p < 0.05) categorical variable association between climate change perceptions and fish catches. However, there are no statistically significant (R2 = 0.08, p > 0.05, n = 30) changes in mean annual temperature from 1987 to 2016. There is a statistically significant increase in rainfall (R2 = 0.14, p < 0.05, n = 30) over the three decades. The results suggest that it is crucial for policy and development agencies to consider the fishers’ perceptions of climate change to formulate appropriate climate responses at the local level.

Lake Victoria fisheries: Outlook and management

AbstractThe past subsistence of the Lake Victoria fishery was dominated by rich, diverse haplochromine cichlids. This multispecies fishery has undergone a decline over the past four decades, evolving into a commercial fishery consisting mainly of Nile perch (Lates niloticus), Nile tilapia (Oreochromis niloticus) and cyprinid (Rastrineobola argentea species). To better understand Lake Victoria fisheries, studies dating as far back as the 1920s have been carried out to assess the status of the fish stocks. These past studies indicated the lake fisheries were declining because of numerous major challenges, including intense fishing, invasive species, loss of biodiversity, ecological alterations, climate change, inadequate information to inform management and unharmonized policies. Numerous policies and regulations have been developed and implemented over the years to address these issues and manage the fisheries sustainably. Most of the interventions have been sectorial, disjointed and unharmonized and have not reduced the declining fish catch rates. With reestablishment of the East Africa Community (EAC) with several institutions in 1994, the Lake Victoria riparian states initiated an ecosystem approach to manage the Lake Victoria fishery resources in a sustainable manner. This study reviews the development of the Lake Victoria fisheries, outlines major past and present management challenges and provides a set of new strategies to manage the lake's fisheries resources, with emphasis on an ecosystem approach.

Rapid declines across Australian fishery stocks indicate global sustainability targets will not be achieved without an expanded network of ‘no‐fishing’ reserves

Abstract A continuing debate between environmental scientists and fisheries biologists on the sustainability of fisheries management practices, and the extent of fishing impacts on marine ecosystems, is unlikely to be resolved without fishery‐independent data spanning large geographic and temporal scales. Here, we compare continental‐ and decadal‐scale trends in fisheries catches with underwater reef monitoring data for 533 sites around Australia, and find matching evidence of rapid fish‐stock declines. Regardless of a high global ranking for fisheries sustainability, catches from Australian wild fisheries decreased by 31% over the past decade. The biomass of large fishes observed on underwater transects decreased significantly over the same period on fished reefs (36% decline) and in marine park zones that allow limited fishing (18% decline), but with a negligible overall change in no‐fishing marine reserves. Populations of exploited fishes generally rose within marine reserves and declined outside the reserves, whereas unexploited species showed little difference in population trends within or outside reserves. Although changing climate and more precautionary fisheries management contribute to declining fish catches, fisheries‐independent transect data suggest that excessive fishing also plays a major role. The large number of fishery stocks that remain unmanaged or have poor data, coupled with continuing declines in the stock biomass of managed fish species, indicate that Aichi Target 6 of the Convention on Biological Diversity (i.e. ‘by 2020, all fish and invertebrate stocks and aquatic plants are managed and harvested sustainably’) will not be achieved in Australia, or elsewhere. In order to maintain some naturally functioning food webs supported by large predators and associated ecosystem services in this era of changing climate, a greatly expanded network of effective, fully protected marine protected areas is needed that encompasses global marine biodiversity. The present globally unbalanced situation, with &gt;98% of seas open to some form of fishing, deserves immediate multinational attention.

Impact of the closed fishing season policy for sardines in Zamboanga Peninsula, Philippines

The closed fishing season policy was imposed on sardines in the Zamboanga Peninsula, Philippines for December 1 to March 1, to allow for a more productive spawning season and address the declining fish catch. Policy inputs were the resources for monitoring compliance to the policy and information campaign to elicit community and other stakeholders’ support. Expected policy output was the increase in fish stock while expected policy impacts included increase in landed catch, decline in incomes of factory workers, increase in incomes of fishers and increase in societal benefits. Primary and secondary data were gathered to analyze impacts in the various sectors. Secondary data came from government sources, canneries and the bottling companies. Primary data were gathered through household surveys, key informant interviews, and focus group discussions with various stakeholders. The social welfare analysis integrated the study results. Results showed an increase in landed catch of sardines after the policy implementation. There was also increase in catch of high value non-sardine species. Incomes of fishing crew increased. Factory wages declined during the months of December to February, although working hours and days increased during open season. Factory workers found alternative livelihoods during the closed season. There was positive impact to society overall. The authors recommend that closed season policy in the Zamboanga Peninsula be continued.

Spread of proliferative kidney disease in fish along stream networks: A spatial metacommunity framework

Abstract Proliferative kidney disease (PKD) is a high‐mortality pathology that critically affects freshwater salmonid populations. Infection is caused by the endoparasitic myxozoan Tetracapsuloides bryosalmonae, which exploits freshwater bryozoans as primary hosts. Incidence and severity of PKD have recently increased, largely owing to rising water temperatures linked to climate change, causing a decline in fish catches and local extinctions in many river systems. Here, building on a recently proposed local model of PKD transmission, a spatially explicit metacommunity framework is developed to study the spatial effects of the disease spread in idealised stream networks. At the local community scale, the model accounts for demographic and epidemiological dynamics of bryozoan and fish populations. At the network scale, the model couples the dynamics of each local community through hydrological transport of parasite spores and fish movement. The model also explicitly accounts for heterogeneity in habitat characteristics and hydrological conditions along a river network. Network effects are investigated by running simulation experiments on synthetic river network replicas derived from Optimal Channel Networks, spanning trees known to reproduce all the mutually connected topological and metric features of real rivers. Network connectivity can produce heterogeneous patterns of PKD prevalence even when the underlying spatial distributions of fish and bryozoans are homogeneous. Prevalence is generally higher at the downstream sites: if fish mobility is neglected, the spatial distribution of prevalence follows that of the upstream drainage area; otherwise, prevalence patterns are correlated with the proximity to the outlet. Downstream invasion speed of PKD is generally high, due to the fast dynamics of hydrological spore transport. For the tested values, effects of water temperature on prevalence heterogeneity are minor. However, climate change may increase invasion speed in both downstream and upstream directions. PKD can establish in bryozoan‐free river reaches, on the condition that the infection be sustained by upstream or downstream hot‐spots. These results further our understanding of the drivers of fish distribution in riverine ecosystems and may provide the basis for the development of intervention and management tools, especially facing climate change.