Week 5 of seed hardening at Point Whitney

Conducting weekly hardening stress on oyster seed at Point Whitney and prepping for Westcott deployment

I did not use AI to conduct the work detailed here and did not use AI to write this notebook post.

Overview

Today I went out to Point Whitney to continue thermal hardening treatments on our new batch of seed and prepare outplants for Westcott deployment in a couple weeks.

I am tracking treatments on this spreadsheet here.

The oysters are being held in silos outsidee. Since the weather has warmed the oysters are exposed to ~20-22°C in the hatchery, which has led us to increase the treatment for hardening to 36°C to maintain a +10°C differential. The control oysters are now staying in the silos while the high treatment are brought into a treatment bucket. Both groups of oysters have temperature loggers attached.

Thermal hardening

I used the following approach to conduct the stress:

• Filled one 5-gallon buckets with seawater (high treatment, control left in silo)
• Added a small recirculating pump and a small titanium heater connected to a thermostat
• I set the thermostat at 36°C and waited until the bucket read at 36°C to add the oysters
• Added oysters to the bucket
• I recorded the temperature and then started a timer for 30 min
• After 30 minutes I removed the oysters and rinsed all the equipment

All of the equipment is stored together on top of a yellow lid box in the attic. Oysters were returned to their ambient temperature upweller tanks outside.

Hardening was conducted from 11:30-12:00 today.

Preparation for outplanting

We have two bags of oysters at Point Whitney for this experiment - a “heated” treatment group and a “control” group. I measured the volume of oysters in each bag (150 mL for both) and then partitioned these oysters into three small mesh bags (orange bags = treated high group; blue bags = control group) that are all contained in the larger original red seed bag with a tag on the outside for each treatment. Each replicate small bag includes about 50 mL of oysters. I counted a subset of oysters and there are approximately 815 in each bag (163 oysters per 10 mL). These oysters are very small (<5mm) and therefore will remain in mesh bags once outplanted until they are large enough to be released into the larger cages.

There are a total of 6 bags from the Point Whitney group that will therefore be outplanted.