Distribution of Lucinoma heroica (Mollusca: Bivalvia: Lucinidae) in the minimum oxygen zone in the Gulf of California, Mexico

Abstract

From samples taken during the oceanographic cruises TALUD IV-X in the southern and central Gulf of California, Mexico, 291 specimens of Lucinoma heroica were obtained in a depth interval of 731 to 991 m. The species occurred under conditions of severe (,0.1 ml l 21 O 2 ) and moderate hypoxia (0.1 -0.5 ml l 21 O 2 ). The correlation between height and length of the shell showed isometric growth with a trimodal size distribution, showing an average interval of 3.75 mm to 47.40 mm in height and 4.96 mm to 54.00 mm in length. Small individuals (≤20 mm) were distributed in a moderate hypoxic environment, while the larger (.35 mm) tolerated an almost anoxic habitat. Medium-sized specimens (21-35 mm) were found in concentration close to 0.2 ml l 21 O 2 . Average density was 1.532 ind l 21 in infauna samples (dredge and core) and 0.002 ind m 22 in epifauna samples (benthic sledge).

ROV’s Video Recordings as a Tool to Estimate Variation in Megabenthic Epifauna Diversity and Community Composition in the Guaymas Basin

“…In our study we found that depth and temperature were also important environmental factors related to variation in the composition of benthic megafauna as reported in other studies of the southern and central regions in the GoC (Hendrickx, 1996(Hendrickx, , 2006Méndez, 2007;Zamorano et al, 2007;Zamorano and Hendrickx, 2012). However, multiple interacting factors ranging from hydrographic (DO, water masses) to food supply and interactions act in synergy with DO and substratum type to influence the structure of these communities.…”

“…On the other hand, low taxonomic richness of megabenthic fauna was observed at depths with reduced DO and greater cover of soft sediment in the LB of the OMZ. Several studies in this region (Méndez, 2007;Zamorano et al, 2007;Zamorano and Hendrickx, 2012;Hendrickx and Serrano, 2014;Hinojosa-Corona, 2014;Hendrickx et al, 2016;Papiol and Hendrickx, 2016) have reported that the OMZ is coupled closely to the diversity, composition, abundance and distribution of megafauna inhabiting the water column and the benthos. Differences in the tolerances of megafauna to OMZ conditions very likely influence the shift in the species composition of communities in the LTZ (Levin, 2003;Gooday et al, 2010).…”

“…In the GoC, low bottom water DO is strongly associated with the density or diversity of a range of taxa, such as Polychaeta (Méndez, 2007), Bivalvia (Zamorano et al, 2007;Zamorano and Hendrickx, 2012) and Decapoda (Hendrickx and Serrano, 2014;Papiol and Hendrickx, 2016). Nevertheless, these studies also document that other factors (e.g., temperature, depth and sediment composition) also influence deep-sea macrofaunal assemblages.…”

“…Preliminary data collected mainly by sledges, dredges and box cores indicate that the southeast GoC has an abundant and diverse deep-sea benthic fauna dominated by polychaetes, decapod crustaceans, echinoderms, and mollusks (Hendrickx, 2006;Lluch-Cota et al, 2007;Méndez, 2007;Zamorano et al, 2007;Zamorano and Hendrickx, 2012;Hendrickx and Serrano, 2014;Hernández-Alcántara et al, 2014;Mejía-Mercado et al, 2014;Papiol and Hendrickx, 2016).…”

Deep-water bivalve mollusks collected during the TALUD XV cruise off the west coast of the southern Baja California Peninsula, Mexico

“…Some species of mollusks (e.g., Lucinoma spp.) are known to tolerate extremely low oxygen concentrations and are able to survive in severe hypoxic conditions ( Zamorano and Hendrickx 2012 ; Vaquer-Sunyer and Duarte 2008 ). Except for two samples (i.e., Jupiteria pontonia and Limatula cf.…”