Mapping and Assessing Commercial Fisheries Services in the Lithuanian Part of the Curonian Lagoon

The spatial distribution of biomass of main commercial fish species was mapped to estimate the supply of a provisioning fishery service in the Curonian lagoon. Catch per unit effort (CPUE) was used as a proxy to estimate the efficiency of commercial fishing and, subsequently, the potential biomass of fishes. The relationship between distinctive characteristics of the fishing areas and corresponding commercial catches and CPUE was analyzed using multivariate analysis. The total catch values and CPUE used in the analyses were derived from the official commercial fishery records. RDE analysis was used to assess the variation of both catch and CPUE of commercial fish species, while the percentages of bottom sediment type coverage, average depth, annual salinity, and water residence time in each of the fishing squares were used as explanatory variables. This distance e-based redundancy analysis allowed for the use of non-Euclidean dissimilarity indices. Fisheries data spatial distribution map indicated the lack of coherence between the spatial patterns of commercial catches and CPUE distribution in the northern part of the lagoon. Highest CPUE values were estimated in the central-eastern part of the lagoon as compared to the western part of the lagoon where CPUE values were substantially lower. Both total catch and CPUE appeared not to be related to the type of bottom habitats statistically while being spatially correlated in-between. However, the impact of salinity and water residence time calculated using the 3D hydraulic circulation model on the distribution of both CPUE and commercial catches was statistically significant.

Impacts of COVID-19 on the Catch of Small-Scale Fishers and Their Families Due to Restriction Policies in Davao Gulf, Philippines

COVID-19 was declared a global pandemic by the World Health Organization in 2020 with countries putting up several measures to mitigate and flatten the curve of hospitalizations and death from travel bans to home confinements and local lockdowns. This pandemic created health and economic crises, leading to increased incidence of poverty and food crisis especially on both agriculture and the fisheries in many developing nations including the Philippines. The specific objectives of this study were to assess the impact of COVID-19 restrictions on the catch per unit effort (CPUE) of small-scale fishers and to determine what factors could influence the volume of their catch during this time of pandemic. Moreover, this also investigated the impact of COVID-19 restrictions to fishers and their families. To do that we surveyed N = 200 small-scale fishers around the Davao gulf using semi-structured questionnaire and inquired on the impact of the COVID-19 to their fishing operation, catch, fishing costs, and their families. The collected socioeconomic variables, including emotional responses to the pandemic were then related to the CPUE and the volume of catch. The results show that fishers were highly affected by the pandemic due to the lockdown policy imposed in the fishing villages during the earlier phases of restrictions by the government. Fishers were affected in terms of the volume of their catch, also fishing costs, and emotionally as they were also frustrated due to the impacts of the hard lockdown. The restricted fishing access was found to have important and major set-back on the fishing operations of fishers and the same was experienced also by the middlemen given the low fish price and reduced mobility of the fish traders. COVID-19 also impacted the fishers, and their families through lack of mobility, food inadequacy, travel restrictions and their children’s education.

Coastal Vegetation and Bathymetry Influence Blue Crab Abundance Across Spatial Scales

Blue crabs (Callinectes sapidus) are highly mobile, ecologically-important mesopredators that support multimillion-dollar fisheries along the western Atlantic Ocean. Understanding how blue crabs respond to coastal landscape change is integral to conservation and management, but such insights have been limited to a narrow range of habitats and spatial scales. We examined how local-scale to landscape-scale habitat characteristics and bathymetric features (channels and oceanic inlets) affect the relative abundance (catch per unit effort, CPUE) of adult blue crabs across a > 33 km2 seagrass landscape in coastal Virginia, USA. We found that crab CPUE was 1.7 × higher in sparse (versus dense) seagrass, 2.4 × higher at sites farther from (versus nearer to) salt marshes, and unaffected by proximity to oyster reefs. The probability that a trapped crab was female was 5.1 × higher in sparse seagrass and 8 × higher near deep channels. The probability of a female crab being gravid was 2.8 × higher near seagrass meadow edges and 3.3 × higher near deep channels. Moreover, the likelihood of a gravid female having mature eggs was 16 × greater in sparse seagrass and 32 × greater near oceanic inlets. Overall, we discovered that adult blue crab CPUE is influenced by seagrass, salt marsh, and bathymetric features on scales from meters to kilometers, and that habitat associations depend on sex and reproductive stage. Hence, accelerating changes to coastal geomorphology and vegetation will likely alter the abundance and distribution of adult blue crabs, challenging marine spatial planning and ecosystem-based fisheries management.

Design and Operation of “Siklob”, a Mechanised Falling Gear Operated in Northern Iloilo, Philippines

Fisheries in the Philippines is multispecies, and this is seen with the wide variety of fishing gears used in major and minor fishing grounds in the country. These gears constantly face modification and development to improve catch quality, quantity, and overall efficiency. This study investigated the features of “siklob”, a mechanised falling gear operated along the municipal waters of Northern Iloilo, Philippines. Some coastal residents claimed that fishers use fine mesh nets for this gear, and this was because of some incidences of the capture of very small fish. Results of this study, however, indicate that the mesh size of nettings used for “siklob” is 4.35 cm, which is above the minimum set by the national law (3 cm). The gear is operated offshore, in a fishing vessel, with lights and fish-finding devices. The catch included an array of pelagic to benthic species, with Sardinella gibbosa (Bleeker, 1849) as the top species. The catch per unit effort values for two fishing operations were 17.40 kg.cast-1 and 16.5 kg.cast-1, respectively. If a management plan for the gear is to be implemented in the area, it would be necessary first to study the spawning seasons of commercially important species and impose closed fishing seasons. Before any attempt to ban or control the use of the gear, it is necessary first to understand the gear design, performance, and selectivity.

Error Distribution Model to Standardize LPUE, CPUE and Survey-Derived Catch Rates of Target and Non-Target Species

Indices of abundance are usually a key input parameter used for fitting a stock assessment model, as they provide abundance estimates representative of the fraction of the stock that is vulnerable to fishing. These indices can be estimated from catches derived from fishery-dependent sources, such as catch per unit effort (CPUE) and landings per unit effort (LPUE), or from scientific survey data (e.g., relative population number—RPN). However, fluctuations in many factors (e.g., vessel size, period, area, gear) may affect the catch rates, bringing the need to evaluate the appropriateness of the statistical models for the standardization process. In this research, we analyzed different generalized linear models to select the best technique to standardize catch rates of target and non-target species from fishery dependent (CPUE and LPUE) and independent (RPN) data. The examined error distribution models were gamma, lognormal, tweedie, and hurdle models. For hurdle, positive observations were analyzed assuming a lognormal (hurdle–lognormal) or gamma (hurdle–gamma) error distribution. Based on deviance table analyses and diagnostic checks, the hurdle–lognormal was the statistical model that best satisfied the underlying characteristics of the different data sets. Finally, catch rates (CPUE, LPUE and RPN) of the thornback ray Raja clavata, blackbelly rosefish Helicolenus dactylopterus, and common mora Mora moro from the NE Atlantic (Azores region) were standardized. The analyses confirmed the spatial and temporal nature of their distribution.

Small-scale fisheries in Madeira: recreational vs artisanal fisheries

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.

Efficient Fishing Method to Control the Population of Rice Eel, Monopterus albus (Synbranchidae) in Rice Fields in Cagayan Valley, Philippines

Rice eel (Monopterus albus) was introduced in the Philippines in 1905 as an aquaculture species without a thorough evaluation of its possible negative impact on the environment. In Cagayan Valley Region, it is being considered as a pest due to the economic loss it brought to farmers as it bore holes on the dikes, draining the water from the rice field, thus, contributing to the additional expense of the farmers. However, from the economic point of view, the species offered great potential as an export commodity due to its broad export market in East Asian countries. Hence, this study was conducted to determine the most efficient and effective method of controlling the proliferation of rice eel in rice fields in the Cagayan Valley region while preserving its integrity as an export commodity. Twelve (12) municipalities were chosen as the study sites based on validated reports of the high occurrence of rice eel. Three fishing methods, namely, fish trap (FT), hook and line (HL), and electrofishing (EF) gadget, were utilized. These gears were set during the dry and wet seasons. Catch and catch per unit effort (CPUE) were used to determine gear efficiency, while monetary values, net income, and ROI were used to assess the profitability of the gears. Results showed that electrofishing gadgets exhibit greater efficiency among the three fishing gears. The EF gadget also has the highest CPUE (4 individuals) per hour while only around 0–1 per hour for FT and HL. Seasonality does not affect the efficiency of the three fishing gears. Also, there is no significant interaction between seasons and fishing gears (p = 0.525). Computed annual net income and return on investment (ROI) is also greater using EF (PHP 407,630.40/ha/year with 569% ROI) compared to HL and FT (net incomes of PHP 113,244.68/ha/year and PHP 161,618.99/ha/year, and 261% and 309% ROI, respectively). However, the use of EF as a control measure should entail restrictions such that only within rice farm areas and not in open waters and only after harvest or before planting with issued EF licenses and permits from BFAR and local ordinances. Higher penalties should also be imposed for illegal use of EF such as use in open waters. As an alternative to EF, a combination of FT and HL with modifications or more environment-friendly fishing gears can be explored to catch and control the rice eel population.

Stock Assessment of the Blue Swimming Crab Portunus pelagicus (Linnaeus, 1758) in Stock Enhancement Sites of Danajon Bank, Central Philippines

The stock status of Blue Swimming Crab (BSC), Portunus pelagicus, locally known as lambay, in Danajon Bank was assessed from June 2019 to September 2020 to monitor the impact of the BSC stock enhancement initiative by the Philippine Association of Crab Processors, Inc. (PACPI) in collaboration with BFAR 7. The stock was assessed based on the indicators, namely, catch per unit effort (CPUE), exploitation rate (E), average size, length at first maturity (Lm), and Spawning Potential Ratio (SPR). Data analysis was done using FAO-ICLARM Stock Assessment Tools (FiSAT) II software and the Barefoot Ecologist’s Toolbox for the Length-based Spawning Potential Ratio (SPR). Results show that BSC dominated the monitored landings accounting for 66% of the overall catch harvested mainly by crab pot and crab net. Higher CPUEs were obtained in the months of July, June, May and August with annual mean observed to be higher than the previous assessment conducted by ECOFISH in Danajon Bank particularly for crab pot. Population characteristics revealed that male crab grew slightly faster having higher asymptotic length (L∞ =21.65cm Carapace Width or CW) and growth constant (K=1.3yr-1) than female (L∞ =21.40cm CW, K=1.28yr-1). Sex ratio of male to female was at 1:1.28 indicating plenty of female crabs were captured than male. Gravid crabs were abundant in May, December, April and October. Recruitment pattern showed two pulses with primary peak occurred in April and May and secondary pulse happened in August and September. Encouraging performance indicator noted from this assessment was on the bigger probability of capture sizes and mean length of commonly caught BSC falling above the recommended catchable size of 10.2 cm CW pursuant to DA-DILG JAO No. 1 s. 2014. Maturity size (Lm) was estimated at 10.54 cm CW, though smaller than the previous reported Lm values in Danajon but still within the threshold. The estimated SPR was 26%, higher than 20% limit reference point but slightly lower than 27% recorded in the assessment done by ECOFISH Project in 2014 to 2015. The present SPR though lower than 30% precautionary threshold however higher than 21% generated in Visayan Sea Region 7 for the same period. The higher SPR in Danajon Bank compared to Visayan Sea maybe credited to the effect of stock enhancement activity implemented in the area, though observation is not yet conclusive. On the other hand, unfavorable indicators were seen on high exploitation rate (E), high exploitation at yield per recruit some of which already breached the optimum level, consequently subjecting Danajon Bank to high fishing pressure. It is recommended to continue the BSC stock enhancement program of PACPI and BFAR 7 taking consideration some strategies for improvement specified in the recommendations.