Essential Market Squid (Doryteuthis opalescens) Embryo Habitat: A Baseline for Anticipated Ocean Climate Change

Abstract

The market squid Doryteuthis opalescens deposits embryo capsules onto the continental shelf from Baja California to southern Alaska, yet little is known about the environment of embryo habitat. This study provides a baseline of environmental data and insights on factors underlying site selection for embryo deposition off southern California, and defines current essential embryo habitat using (1) remotely operated vehicle-supported surveys of benthos and environmental variables, (2) SCUBA surveys, and (3) bottom measurements of T, S, pH, and O 2 . Here, embryo habitat is defined using embryo capsule density, capsule bed area, consistent bed footprint, and association with [O 2 ] and pH (pCO 2 ) on the shelf. Spatial variation in embryo capsule density and location appears dependent on environmental conditions, whereas the temporal pattern of year-round spawning is not. Embryos require [O 2 ] greater than 160 mmol and pH T greater than 7.8. Temperature does not appear to be limiting (range: 9.9°C-15.5°C). Dense embryo beds were observed infrequently, whereas low-density cryptic aggregations were common. Observations of dense embryo aggregation in response to shoaling of low [O 2 ] and pH indicate habitat compression. Essential embryo habitat likely expands and contracts in space and time directly with regional occurrence of appropriate O 2 and pH exposure. Embryo habitat will likely be at future risk of compression given secular trends of deoxygenation and acidification within the Southern California Bight. Increasingly localized and dense spawning may become more common, resulting in potentially important changes in market squid ecology and management.

Dose-dependence and small-scale variability in responses to ocean acidification during squid, Doryteuthis pealeii, development

“…Reported shelf carbonate system profiles across D. pealeii egg laying habitat suggest a potential exposure range of 8.2 -7.88 pH t during breeding season (250 -600 ppm CO 2 ; values calculated across depth/temperature extremes using CO 2 SYS with data from Wang et al 2013). Whether pH or others oceanographic parameters, such as oxygenation, determine D. pealeii egg laying habitat has not been reported to our knowledge, but observations of the California market squid, Doryteuthis opalescens, demonstrate a preference for oxygen levels greater than 160 µmol and pH t greater than 7.8 (Navarro et al 2018).…”

Dynamic spawning patterns in the California market squid (Doryteuthis opalescens) inferred through paralarval observation in the Southern California Bight, 2012–2019

“…This study marks the first attempt to sample and understand the fine-scale spawning patterns in market squid by conducting multiple surveys within a single hatching season. Although market squid spawn at low levels throughout the year (Navarro et al, 2018;Zeidberg et al, 2012), the vast majority of paralarvae are observed during the winter hatching season in the SCB (Van Noord & Dorval, 2017); this study provides insight into those spawning patterns.…”

“…For an aggregation of spawning squid to amass and initiate spawning, a suite of abiotic and biotic attributes must be realized. For example, the habitat must be in relatively shallow water, over predominately sandy substrate, within certain temperature, nutrient, and chemical thresholds (Navarro et al., 2018; Zeidberg et al., 2012; Zeidberg, Isaac, Widmer, Neumeister, & Gilly, 2011). Once those criteria are met, the exact location of spawning aggregations may be somewhat random and resultant on an initial seed population that colonizes a given area.…”

“…While not ideal (Okutani & McGowarn, 1969), many researchers have developed indices to use larval abundance to predict adult biomass (Lo et al., 2010) and use larval and paralarval abundance to gain insight into adult spawning dynamics (Sakurai, Kiyofuji, Saitoh, Goto, & Hiyama, 2000; Smith & Moser, 2003; Zeidberg et al., 2006). Furthermore, it is extremely difficult to obtain direct, broad‐scale spawning and embryo information (see methods by Navarro, Parnell, & Levin, 2018). Therefore, to gain insight into these spawning patterns the following was specifically asked: (a) Is there a large‐scale synchronous peak in paralarvae abundance?…”

Antagonistic Interactions and Clutch-Dependent Sensitivity Induce Variable Responses to Ocean Acidification and Warming in Squid (Doryteuthis pealeii) Embryos and Paralarvae

“…Less is known about the preferences for pH of egg laying habitat for this species, but pH t calculated from shelf carbonate system profiles throughout their habitat range indicate a typical exposure range of 7.88-8.2 (600-250 ppm pCO 2 ) during the breeding season (Wang et al, 2013;Zakroff et al, 2019). Navarro et al (2018) reported preferred egg laying habitat for the California market squid, Doryteuthis opalescens, as requiring pH t greater than 7.8 and O 2 concentrations greater than 160 µmol with no apparent temperature limitation within the region. These static ranges do not account for the possible variability of temperature and carbonate system measures across temporal scales, as have Abbreviations: DML, dorsal mantle length; ESL, Environmental Systems Laboratory; KW, Kruskal-Wallis test; LR, linear regression; MBL, Marine Biological Laboratories; OA, ocean acidification; YV, yolk sac volume.…”