A bloodbath of mussels as algae bloom hits the Berkeley Marina

On Monday afternoon, Paul Kamen kayaked within the Berkeley Marina harbor. The sky was blue, the solar shiny, and the ocean breeze light. However one factor was amiss: the water had turned a red-brown, virtually chocolatey hue. 

“I’ve been coming right here since 1973,” stated Kamen, a longtime Berkeley sailor, consulting naval architect, and former Waterfront commissioner. “I’ve by no means seen something prefer it.”

Then there was the stench, or as one Berkeleyside reader put it: a “distinctive porta-potty scent” coming from the water. A number of docks had been changed into a makeshift seafood buffet by the gulls, which hopped round merrily and feasted on the piles of lifeless and dying mussels, often choosing up shells greater than their beak. 

Scientists say these mussel deaths are doubtless related to a purple tide of Heterosigma akashiwo, microscopic algae which have been noticed within the Bay since at the least July, from Fremont to San Pablo Bay. Based on the environmental group SF Baykeeper, “a bloom of this magnitude has not occurred within the area since 2004.” 

Whereas toxicity to people or pets has not been documented within the scientific literature, some native jurisdictions are warning residents to keep away from water contact on a precautionary foundation. Berkeley spokesperson Matthai Chakko stated town is ready on steering from state and regional water board companies. 

Like different affected marine life, the mussels are most likely dying as a result of they will’t breathe.

When excessive temperatures coincide with water excessive in vitamins, the algae grows so prolific that it begins to eat the entire oxygen accessible, inflicting fish and different lifeforms to suffocate. Jonathan Shurin, an ecology professor at UC San Diego, likened it to overfeeding fish in a fish tank: “In case you overfeed your fish in your fish tank, it might probably die, and it’s not as a result of they eat an excessive amount of. It’s since you’re overfeeding the micro organism within the water, and it makes use of up all of the oxygen … after which the fish suffocate.”

This might be what’s driving the die-off. Or the algae itself might be poisonous. Or each. Scientists nonetheless aren’t positive. What’s unlikely is that it’s warmth alone, since there hasn’t been a significant warmth wave alongside the coast this month. 

The Berkeley Marina hasn’t seen the kind of apocalyptic mass fish loss of life seen in Oakland’s Lake Merritt. Its place subsequent to open water permits some species to swim out of the way in which of the algae and into deeper waters, the place they will breathe.

Mussels aren’t so fortunate. They’re sessile, that means they, very similar to timber, are dispersed as larvae and discover a place to settle, the place they develop into maturity.

Mussel beds are “kind of like coral reefs,” Shurin stated, in that they’re habitats for different species. “If the mussel mattress is totally gone for some time period, then all these different species could undergo.”

The gulls consuming the decaying mussels can be high-quality, although, he added. “They eat rubbish on a regular basis.”

The place did the algae come from?

The bloom of Heterosigma akashiwo is pure and happens each few years, however not often in such unbelievable abundance. 

Damon Tighe is searching for extra volunteers to assist doc the wildlife impacts of the algal bloom. No expertise in figuring out species is required — only a cellphone digital camera. 

Damon Tighe, a group naturalist who paperwork wildlife at Lake Merritt, defined that this organism is all the time current within the water, however it spends a part of its life in a “cyst” kind, just like a seed that floats or rests within the sediment, ready till the circumstances are proper to develop, bloom, and reproduce.

For quite a lot of causes we don’t but absolutely perceive, the circumstances are nice proper now for Heterosigma akashiwo to develop. We do know that the algae want nitrogen and phosphorus to feed on. Some have speculated that wastewater outflows into the Bay from the various sewer districts the place human and industrial waste movement might be offering these vitamins. 

A examine of a purple tide that killed fish in Florida final yr confirmed that wastewater worsened the lethal occasion for fish and different wildlife. Others marvel if there was extreme runoff from agricultural fields within the Central Valley this yr.