Table of Contents

• Coverage
• Dataset Description
  • Methods & Sampling
  • Data Processing Description
• Data Files
• Related Publications
• Related Datasets
• Parameters
• Instruments
• Project Information
• Funding

Juvenile Black sea bass (BSB) were caught on September 3rd (collection 1) and 21st 2021 (collection 2) via beach seine (30 × 2 meters) in Mumford Cove (41° 19' 25"N, 72° 01 '07"W), a shallow protected bay with extensive eelgrass cover in eastern Long Island Sound, USA.

Experiment 2 quantified juvenile winter growth and lipid accumulation under seasonally varying food and temperature conditions over the course of 182 days (October 1, 2021 to April 1, 2022). Initial total length (TL, mean ± SD = 70.9 ± 5.4 millimeters (mm)) and wet weight (wW, mean ± SD = 4.4 ± 0.9 grams (g)) were determined on briefly anesthetized specimens, followed by randomly distributing 48 juveniles into individual 20-liter (L) rearing containers with mesh-screened holes, an air stone, and a PVC hide. An additional baseline sample (n = 25, mean ± SD TL = 71.4 ± 9.4 mm, wW = 4.7 ± 1.8g) was euthanized and stored at -20° Celsius (C). We then used six 700 L recirculating tanks to each house eight individual BSB rearing containers (mean maximum stocking density = 0.13 kilograms per cubic meter (kg m⁻³). Tanks (n = 2 tanks per treatment; n = 8 containers per tank) were randomly assigned to one of three seasonally varying food treatments (Otohime C1 pellets) designed to simulate three phases of contrasting overwinter food availability for BSB juveniles. The 'Winter dip' treatment was fed 5% body wW 3× weekly during Phase 1 ("Fall": October, November), 2% wW 3× weekly during Phase 2 ("Winter": December – February) and again 5% body wW 3× weekly during Phase 3 ("Spring": March). This was to simulate a scenario of good onshore feeding conditions for juveniles in fall and spring, but poorer feeding conditions at their offshore overwintering habitats. Conversely, our 'Winter pulse' treatment was to simulate poor fall and spring feeding conditions for juveniles onshore by feeding 1% wW 3× weekly during Phase 1 and 3, but 2% wW during Phase 2, thereby simulating the same offshore winter feeding conditions (Fig.2A of Zavell et al. (in review)). Last, we included a 'Constant' treatment as control, which fed 2% wW 3× weekly throughout the entire six months of rearing (Phases 1-3). Food rations were based on both Cotton (2002), who showed no difference in growth at rations of 5 - 7.5% wW, but reduced growth at 2.5% wW and Watanabe et al. (2021) who report ideal feeding rates between 3 – 5% wW. For all treatments, rations were individually recalculated after the 1ˢᵗ of each month, based on re-measured wW and TL on briefly anesthetized fish.

Temperature conditions in Exp2 were recorded in 30 minute intervals using HOBO temperature loggers (Onset MX^®).

Response traits. Initial, monthly (Exp2 only), and final measurements of individual fish (TL, wW) were used to calculate total (final – initial), cumulative (end of month – initial), and/or serial (end of month – start of month) growth (e.g., cumulative and serial DTL for month 2 = TL_d61 – TL_d0 and TL_d61 – TL_d31), respectively) and average daily growth rates (growth/days in growth interval). Specific growth rates (SGR; % wW per day) were calculated similarly but used ln(wW) at each time period (e.g., 100*[ln(wW_d61)-ln(wW_d31)]). Growth efficiency (GE, %) was calculated cumulatively (Exp1, Exp2) and monthly (Exp2 only) as the change in body dry weight (DdW_b, g) divided by total food consumed (DF, g) during a given time interval. (In Exp2, three GE values > 100% were excluded as outliers). Q₁₀ values (Exp1) were calculated for GR, SGR, and GE between 6-12°C and 12-19°C.

For each experiment, we also determined the lipid, lean, and ash dry weights of each surviving BSB juvenile and those of the baseline samples. Whole specimens were first transferred to -80°C for one week, then freeze-dried at -50°C for one week and re-measured for whole body dry weight (dW_b, 0.001 g). Dried specimens were then loaded into pre-weighed Alundum medium-porosity extraction thimbles and transferred into a custom-designed Soxhlet apparatus, where they were bathed in petroleum ether for a total of 3.5 hours to extract all metabolically accessible lipids (15-minute cycles of bathing, flushing, and ether replacement). After extraction, thimbles were dried overnight at 60°C and re-weighed to determine DdW, which equaled the total lipid content (dW_Lipid, milligrams (mg)) of each specimen after accounting for any tissue loss during transfer from vial into thimble. Thimbles were then placed in a muffle furnace for 4 hours at 550°C and re-weighed, with DdW during this second step corresponding to a fish's lean mass (dW_Lean, mg), again after accounting for any tissue loss during transfer from vial into thimble. The difference between the final weight and the pre-weighed empty thimble equaled ash (dW_Ash, mg), i.e., the inorganic fraction of each individual.

BCO-DMO Processing:
- Imported original file named "BCO-DMO-Source-BSB-Juvenile-Overwintering-V2.xlsx" sheet 3 into the BCO-DMO data system;
- renamed fields to comply with BCO-DMO naming conventions (replaced spaces with underscores);
- converted dates to YYYY-MM-DD format;
- added columns for latitude and longitude in decimal degrees;
- rounded values to 3 decimal places;
- named the final file "898012_v1_bsb_experiment2.csv".

Description from NSF award abstract:
Coastal marine ecosystems provide a number of important services and resources for humans, and at the same time, coastal waters are subject to environmental stressors such as increases in ocean acidification and reductions in dissolved oxygen. The effects of these stressors on coastal marine organisms remain poorly understood because most research to date has examined the sensitivity of species to one factor, but not to more than one in combination. This project will determine how a model fish species, the Atlantic silverside, will respond to observed and predicted levels of dissolved carbon dioxide (CO2) and oxygen (O2). Shorter-term experiments will measure embryo and larval survival, growth, and metabolism, and determine whether parents experiencing stressful conditions produce more robust offspring. Longer-term experiments will study the consequences of ocean acidification over the entire life span by quantifying the effects of high-CO2 conditions on the ratio of males to females, lifetime growth, and reproductive investment. These studies will provide a more comprehensive view of how multiple stressors may impact populations of Atlantic silversides and potentially other important forage fish species. This collaborative project will support and train three graduate students at the University of Connecticut and the Stony Brook University (NY), two institutions that attract students from minority groups. It will also provide a variety of opportunities for undergraduates to participate in research and the public to learn about the study, through summer research projects, incorporation in the "Women in Science and Engineering" program, and interactive displays of environmental data from monitoring buoys. The two early-career investigators are committed to increasing ocean literacy and awareness of NSF-funded research through public talks and presentations.

This project responds to the recognized need for multi-stressor assessments of species sensitivities to anthropogenic environmental change. It will combine environmental monitoring with advanced experimental approaches to characterize early and whole life consequences of acidification and hypoxia in the Atlantic silverside (Menidia menidia), a valued model species and important forage fish along most of the US east coast. Experiments will employ a newly constructed, computer-controlled fish rearing system to allow independent and combined manipulation of seawater pCO2 and dissolved oxygen (DO) content and the application of static and fluctuating pCO2 and DO levels that were chosen to represent contemporary and potential future scenarios in productive coastal habitats. First CO2, DO, and CO2 × DO dependent reaction norms will be quantified for fitness-relevant early life history (ELH) traits including pre- and post-hatch survival, time to hatch, post-hatch growth, by rearing offspring collected from wild adults from fertilization to 20 days post hatch (dph) using a full factorial design of 3 CO2 × 3 DO levels. Second, the effects of tidal and diel CO2 × DO fluctuations of different amplitudes on silverside ELH traits will be quantified. To address knowledge gaps regarding the CO2-sensitivity in this species, laboratory manipulations of adult spawner environments and reciprocal offspring exposure experiments will elucidate the role of transgenerational plasticity as a potential short-term mechanism to cope with changing environments. To better understand the mechanisms of fish early life CO2-sensitivity, the effects of temperature × CO2 on pre- and post-hatch metabolism will be robustly quantified. The final objective is to rear silversides from fertilization to maturity under different CO2 levels and assess potential CO2-effects on sex ratio and whole life growth and fecundity.

Related references:
Gobler, C.J. and Baumann, H. (2016) Hypoxia and acidification in ocean ecosystems: Coupled dynamics and effects on marine life. Biology Letters 12:20150976. doi:10.1098/rsbl.2015.0976

Baumann, H. (2016) Combined effects of ocean acidification, warming, and hypoxia on marine organisms. Limnology and Oceanography e-Lectures 6:1-43. doi:10.1002/loe2.10002

Depasquale, E., Baumann, H., and Gobler, C.J. (2015) Variation in early life stage vulnerability among Northwest Atlantic estuarine forage fish to ocean acidification and low oxygen Marine Ecology Progress Series 523: 145–156.doi:10.3354/meps11142