Wrasse consume many molluscs and crustaceans, and play a key role controlling
populations of sea urchins that can deplete seafloor kelp forests — vital sanctuaries for many marine species including young cod.
Not exact matches
A new study suggests that an aggressive reef competitor — the Threespot Damselfish — may have impeded the recovery
of Caribbean long - spined
sea urchin populations after a mysterious disease outbreak caused a massive die - off
of these animals over three decades ago.
For example just a small number
of sea otters can determine
urchin numbers, or a few grey wolves determine the size
of bison, deer or elk
populations.
In a well - studied example from Alaskan kelp forests, [24]
sea otters (Enhydra lutris) control
populations of herbivorous
sea urchins through predation.
[76] Reintroduction
of sea otters to British Columbia has led to a dramatic improvement in the health
of coastal ecosystems, [77] and similar changes have been observed as
sea otter
populations recovered in the Aleutian and Commander Islands and the Big Sur coast
of California [65] However, some kelp forest ecosystems in California have also thrived without
sea otters, with
sea urchin populations apparently controlled by other factors.
They keep the
population of certain benthic (
sea floor) herbivores, particularly
sea urchins, in check.
Today, California sheephead, spiny lobsters, and sunflower stars are the primary consumers
of sea urchins that help keep their
populations in check.
Reintroduction
of sea otters to British Columbia has led to a dramatic improvement in the health
of coastal ecosystems, [143] and similar changes have been observed as
sea otter
populations recovered in the Aleutian and Commander Islands and the Big Sur coast
of California [144] However, some kelp forest ecosystems in California have also thrived without
sea otters, with
sea urchin populations apparently controlled by other factors.
Without
sea otters,
sea urchin populations eventually exploded and overgrazed the kelp, leaving behind large areas
of «
urchin barrens.»
Due to the intact connectivity
of the extensive seagrass beds, desnse mangrove forests, and robust coral reefs, the remoteness
of the area, and the history
of protection from coastal development, the Gardens
of the Queen represents a «baseline» for a nearly pristine Caribbean marine ecosystem; an ecosystem that includes healthy
populations of apex predators like sharks and groupers, important grazers like Rainbow parrotfish and long - spine
sea urchins, and recovering endangered species like elkhorn coral and hawksbill
sea turtles.
Populations of parrotfish are a critical component
of that herbivory, particularly since the decline
of Diadema
sea urchins in the early 1980s; the main causes
of mortality
of parrotfish are the use
of fishing techniques such as spearfishing and, particularly, the use
of fish traps....
Otters had kept
sea urchin populations down, but once their
population was drastically reduced,
urchins feasted on kelp to the point
of over-consumption.
If exposure to a more acidic pH caused a decline in some
sea urchin populations, how might this affect the storage
of carbon in ocean sediments?