The population of Alaskan Snow Crab coastal waters has plummeted by 10 billion due to rising sea temperatures caused by heatwaves. Snow crabs (Chionoecetes opilio) are cold-water species typically found in areas with water temperatures below 2°C, with only a few able to survive in temperatures up to 12°C. In the frigid waters of the Bering Sea near Alaska, these crabs usually inhabit depths with temperatures below 1.6°C.
Researchers previously discovered a significant decline in the snow crab population released in Alaskan waters between 2018 and 2021. Approximately 10 billion snow crabs, or around 90% of the population, are estimated to have vanished.
Warm Ocean Waves and Food Competition
A study revealed that one of the primary causes of the snow crab population decline in the Bering Sea was the heatwaves in 2018 and 2019. Warmer seawater likely disrupts the crabs’ metabolism and increases their calorie requirements. The heatwaves also force the crabs to search for more food to survive in the rising water temperatures.
“From 2017 to 2018, their calorie needs to be increased fourfold,” says Cody Szuwalski, a biologist at the National Oceanic and Atmospheric Administration (NOAA).
Experts note that during the heatwave period, snow crabs had to compete with larger crab populations in 2018 for food. With limited food availability, many snow crabs faced hunger and death, while the survivors tended to have smaller body sizes.
Impact of Heatwaves on Marine Ecosystem
The heatwaves don’t just affect snow crabs; they disrupt the entire marine ecosystem. Other species like Pacific cod take advantage of warmer water temperatures to invade crab habitats and prey on snow crabs. In addition to crabs, salmon, seabirds, and seals are also affected.
Kerim Aydin, a biologist at the Alaska Fisheries Science Center NOAA, states that heatwaves can create widespread famine. Some species, such as pollock and walleye pollock, adapt more quickly to warmer waters.
Researchers suggest that this phenomenon could permanently alter the makeup of species in the Bering Sea.
Financial Impact on the Fishing Industry
Alaskan snow crabs have played a vital role in the commercial fishing industry, valued at over $150 million. However, as snow crab populations decline, the industry’s earnings have dropped, causing financial difficulties for those dependent on crab fishing.
This situation represents of the most significant losses reported among marine fauna due to global marine heatwaves.
Conclusion
In the future, studies will need to consider the effects of rapid climate change when devising conservation plans. Additionally, existing models and management systems will need to be reevaluated in light of these climate-driven changes.
In summary, the unexpected decline in the snow crab population in Alaska’s coastal waters is attributed to warming ocean temperatures driven by heatwaves. This has not impacted the crabs but also disrupted the broader marine ecosystem, leading to financial challenges for a reevaluation of conservation strategies in the face of climate change.