Documenting recovery of a spawning aggregation through size frequency analysis from underwater laser calipers measurements

The Return of the King of the Kelp Forest: Distribution, Abundance, and Biomass of Giant Sea Bass (Stereolepis gigas) off Santa Catalina Island, California, 2014-2015

“…If the giant sea bass population off southern California is indeed recovering, then there is likely to be a larger proportion of smaller and younger fish within the population, which could manifest as a positive skew in length frequencies of the population (Heppell et al 2012). In the case of a spawning aggregation, smaller size classes represent newly mature fish entering the reproductive population.…”

“…However, anecdotal reports by the recreational dive community today suggests that historical spawning aggregations are returning primarily off La Jolla, Santa Catalina Island, and Anacapa Island, California. Surveying spawning aggregation sites allows for a unique opportunity to access a larger percentage of the reproductive population that would otherwise be spread over a greater geographic distribution (Johannes et al 1999, Whaylen et al 2004, Heppell et al 2012). Furthermore, with information on a spawning aggregation biomass, through a length-weight relationship for the species and an estimate of total abundance, the spawning stock biomass of a species can be estimated (Jennings et al 1996).…”

“…Our study applies underwater visual censuses (UVC) using length calibrated lasers for more precise size estimation (Gingras et al 1998, Colin et al 2003, Heppell et al 2012 to provide the first population assessment of the endangered tertiary carnivore, the giant sea bass, of the rocky reefs and kelp forests off southern California at Santa Catalina Island, CA. The objectives of this study were to 1) identify and document spawning aggregation sites and peak aggregation periods throughout the summers of 2014 and 2015; and 2) establish baseline mean densities, stock biomass, and length/biomass distribution frequencies to compare with historical fish surveys.…”

Historical Processes and Contemporary Anthropogenic Activities Influence Genetic Population Dynamics of Nassau Grouper (Epinephelus striatus) within The Bahamas

“…Global declines in Nassau grouper abundance and the disappearance of historic FSAs have led to IUCN-Red List and United States Endangered Species Act designations of endangered and threatened respectively (Cornish and Eklund, 2003;Albins et al, 2009). This has helped to focus conservation management efforts with fisheries management regulations now implemented in a number of countries where Nassau grouper still exist, with recent reports from the Cayman Islands and the United States Virgin Islands of population recovery (USVI; Kadison et al, 2010;Heppell et al, 2012). More generally, however, stock assessment data are deficient and marked declines in commercial landings, FSA abundance and densities on reef habitats have been documented in The Bahamas despite regulatory policies Dahlgren et al, 2016b;Sherman et al, 2016;Stump et al, 2017).…”

Marine Conservation Outcomes are More Likely when Fishers Participate as Citizen Scientists: Case Studies from the Mexican Mesoamerican Reef

“…In the Cayman Islands, scientific characterization efforts from the national government's Department of Environment, with support from the international NGO REEF, led to the protection of an important Nassau Grouper FSA, which has since shown impressive recovery (Heppell et al 2012). However, the scientific efforts for characterization and monitoring did not include most local fishers, thus the fishing community has perceived the closure negatively.…”