Retelling the History of the Red Sea Urchin Fishery in Mexico

Abstract

The red sea urchin fishery has a long harvest and management history along the Northeastern Pacific coast. In Mexico, it has been commercially harvested since 1972, and although it is one of the most important fisheries in Baja California, efforts to assess the condition and dynamics of harvestable stocks have been focused on certain harvested areas with scarce fisheries independent data. Additionally, the analysis of yearly information for small geographic areas has obscured the actual status of harvested populations. This study aims to reassess population trends, fishing effort, and catches, incorporating all available information from the last 19 years. Information was grouped based on 14 landing sites along Baja California's Pacific coast. Length based virtual population analysis (LVPA) was implemented to estimate site-specific catch rates and densities. Red sea urchin catches/landings varied widely within and between areas. Population density was below 1 urchin m −2 in most of the sites, and was composed of higher recruits and juvenile densities that may partially mitigate for fishery removals. LVPA produced biomass estimations that double previous estimates. We suggest that the model parameters used in previous estimations might not reflect key biological traits of the red sea urchin, failing to reproduce population trends accurately. Results from this study allowed identifying the specific sites where population attributes (biomass, densities), fishery data (catch, effort), and the combination of both (Kobe plots), suggest that urchin populations may need attention. New management measures must be adopted: maximum legal size of 110 mm, improvement on fishery logs and analysis, continuous fishery independent surveys to track changes in the population that might not be so apparent when observing only catch/biomass data. Reinforce the under legal size management strategy, since results suggest that sites with high abundances of small urchins can support higher catches.

Understanding the impact of environmental variability and fisheries on the red sea urchin population in Baja California

“…recruitment rates, frequency, or patterns for red sea urchins in Baja California, however, the observed catch trends for the period being analyzed here could be related to constant settlement and recruitment (Medellıń-Ortiz et al, 2020), and consistent with Southern California's recruitment patterns observed by Ebert et al (1994). Also, Medellıń-Ortiz et al (2020), found that over-harvesting in some sites depleted temporarily legal-size urchins without altering population recruitment. This effect has also been described for red sea urchins in Southern California (DeWees, 2004;Stevenson et al, 2016).…”

“…Harvest depends not only on urchin density but also on roe yield and quality, fishable days due to weather, and market conditions (Kato, 1972;Kato and Schroeter, 1985;Kalvass and Hendrix, 1997;Kalvass and Rogers-Bennett, 2001;Andrew et al, 2002;Schroeter et al, 2009;Medellıń-Ortiz et al, 2020). Roe yield depends entirely on food availability (kelp and drift kelp; see Rennick et al, 2022), and is determined by the diver in a preharvest sampling at the beginning of the dive.…”

“…Red sea urchin population status has recently been assessed in Baja California, and findings suggest that variation among stocks is common (Medellıń-Ortiz et al, 2020); however, the causes of population variation are not well understood. As one of the oldest, most economically and socially important fisheries in Baja California, this study aims to understand how local, regional, and oceanic scale variability affects red sea urchin density.…”

Using a social-ecological systems perspective to identify context specific actions to build resilience in small scale fisheries in Mexico

“…The participation of a cross-sectoral consortium in management decisions will also contribute to smart decision making to cope with climate variability in the region. Red sea urchin populations in ITS have presented high historical variability; however, ITS has been identified as one of sites with the highest population density of this species in Baja California (Medellıń-Ortiz et al, 2020). On the contrary, a notable decrease in sea cucumber abundance in the region has been observed (Chavez et al, 2011) despite similar management strategies being implemented as those for the urchin fishery.…”

“…This study has compiled and integrated relevant information of the ITS SES resource system and resource units to document its productivity, sustainability, and adaptive capacity. For example, subtidal community structure, Landsat biomass estimations, physical and chemical oceanographic parameters, and fishing data were integrated (Palleiro-Nayar, 2013;Beas-Luna and Ladah, 2014;Beas-Luna et al, 2020;Medellıń-Ortiz et al, 2020). The integration of this information must be accessible to users to facilitate the design and implementation of adaptive management strategies.…”