Bit by bit the team is circling around the entire coast of Lough Hyne, surveying for key organisms in the intertidal and shallow subtidal zones. We survey the Lough in sectors, following the historical markers first designated by Louis Renouf, a pioneer researcher who is in large part responsible for initiating the long standing scientific interest and research in Lough Hyne.
Jill Lundquist and I headed out to survey the eastern shore just north of the tidal rapids. The first task, get to the other side. It doesn’t seem so difficult until you suddenly find yourself swimming diagonally, headed for the whirlpool, and kicking as hard as you can to make it across. (Imagine you’re going straight and then all of a sudden a gust of water pushes you perpendicular to your path.) Immediately upon making the crossing, we could see that the fight was well worth the effort. Once we made it to the other side, we saw a habitat that is dramatically distinct from where we’d come. Unlike most of the southern shore of the Lough which is predominantly large boulders, sandy bottom, and mats of ephemeral algae, the south-eastern shore is a kelp forest. The kelp creates an environment hospitable for all kinds of organisms that are rare or absent in other parts of the Lough such as spider crabs, feather duster worms, jewel anemones, cushion stars and schools of fish, to name a few.
Jill Lundquist and I headed out to survey the eastern shore just north of the tidal rapids. The first task, get to the other side. It doesn’t seem so difficult until you suddenly find yourself swimming diagonally, headed for the whirlpool, and kicking as hard as you can to make it across. (Imagine you’re going straight and then all of a sudden a gust of water pushes you perpendicular to your path.) Immediately upon making the crossing, we could see that the fight was well worth the effort. Once we made it to the other side, we saw a habitat that is dramatically distinct from where we’d come. Unlike most of the southern shore of the Lough which is predominantly large boulders, sandy bottom, and mats of ephemeral algae, the south-eastern shore is a kelp forest. The kelp creates an environment hospitable for all kinds of organisms that are rare or absent in other parts of the Lough such as spider crabs, feather duster worms, jewel anemones, cushion stars and schools of fish, to name a few.
One of the primary goals of the survey is to track the urchin populations, and within this area one of the local urchin species is particularly abundant. The pink sea urchin, Echinus esculentus, with its sterling white spines and bright pink test (the endoskeleton of the urchin from which the spines protrude), stands out among the dense flora like a beacon with, even when partially covered with algae. Jill scoured the deeper areas, diving down along the slope, while I search the shallows. By the time we had finished surveying a single sector we had amassed a count of nearly 100 urchins, without invasively flipping rocks or digging around in the algae, which means there are likely many more that those that we observed.
Echinus esculentus is of particular interest because of its importance in controlling the different algae in the Lough. Given the recent crash of the population of the other dominant urchin species, the purple urchin Paracentrotus lividus, and the subsequent changes in the algae community composition documented by Cynthia Trowbridge, Colin Little, and Rob McAllen (among others), tracking the population of E. esculentus is especially important. E. esculentus is one of the few large macrophagous grazers in the Lough and plays an important role in shaping the algal community (the foundation of the food web) in the south basin where these urchins are most abundant. This is only a snapshot of the urchins in one small area, but it provides some indication of the current population size of E. esculentus in Lough Hyne. We still have many sectors to survey before we’ll have a more complete picture, but this one sector at least is looking good.
-Sara Edquist
-Sara Edquist