Assessment of the stock status of small-scale and multi-gear fisheries resources in the tropical Eastern Pacific region

Toward Ecosystem-Based Assessment and Management of Small-Scale and Multi-Gear Fisheries: Insights From the Tropical Eastern Pacific

“…Some of the observed differences were related to the interaction between gear type and geographical location of the coastal zones. Despite being in a traditionally data-poor tropical SSF context, our data sets, produced by a non-government organization and by an academic research project, included higher sampling frequency, sample size and geographic coverage than normal government fisheries data (Ramírez et al, 2017;Herrón et al, 2018). Community-based fishing monitoring schemes (as those followed in the present study) are therefore useful and likely more effective and less expensive ways of monitoring fisheries resources in typical SSF like the ones evaluated here.…”

“…However, national assessments of commercially important species have generally been based on stock assessments with limited landings time-series or with poor spatial coverage. This could impose biases and is a common situation in data-limited tropical SSFs assessments (Costello et al, 2012;Ramírez et al, 2017;Herrón et al, 2018). On the other hand, the high proportion of Not Evaluated (NE) species in the catch of SSF, based on national assessments (Table 5), highlights the need to collect data on the status of natural populations based also on fishery-independent surveys.…”

“…Traditional management approaches like catch-quotas and size limits for target species exhibit several practical difficulties when tried to be implemented in multi-gear and multi-species tropical SSF (Salas et al, 2007;Purcell and Pomeroy, 2015). Furthermore, the establishment of catch-quotas, one of the most common management measures, depends on reliable assessments of the target stock size and condition of main target species but these type of assessments are often hindered by low quality of the data available, high uncertainties underlying length-frequency catch data and lack of knowledge of basic growth and reproduction features of target species (Froese, 2004;Cope and Punt, 2009;Ramírez et al, 2017;Herrón et al, 2018).…”

Indicators of stock status for large-pelagic fish based on length composition from driftnet fisheries in Zanzibar

“…By-catch ratios greatly vary between areas and type of fisheries, but discard ratios for those fisheries can be as high as 60% (Dagorn et al, 2013). Schwamborn et al, 2018) are being used to derive reference levels to quantify uncertainty in catch data (Herrón et al, 2018), and could be applied to species such as CPH. As this study shows, length measurements are easy and cost-efficient to collect, even without the necessity of owning or damaging sampled fish;…”

Comparing feeding niche, growth characteristics and exploitation level of the giraffe catfish Auchenoglanis occidentalis (Valenciennes, 1775) in the two largest artificial lakes of northern Ghana

“…turns positive). A seasonally oscillating VBGF was used to assess the growth parameters, because seasonal changes in the growth of tropical fish have frequently been reported, which are attributed to changes in water temperature, precipitation and/or to the availability of food (Morales-Nin and Panfili 2005;Herrón et al 2018). The bootstrapped ELEFAN with genetic algorithm optimisation (bootstrapped ELEFAN with genetic algorithm (GA)) function of TropFishR (Mildenberger et al 2017;Schwamborn et al 2019) was used to determine the parameters L ∞ and K of the von Bertalanffy equation.…”