To eat or be eaten

Figure 1. The experimental set up of temperature effect on predator-prey interactions is depicted in the diagram. Fathead minnows were kept in one tank, which was placed close to a separate tank with the yellow perch. Two feeding devices were used: the one closer to the yellow perch tank was considered the high-risk feeder and the one further way, the low-risk feeder. For trials where no predator is present, a divider between the tanks was used to hide the predator.

By Arina Favilla, SRC intern When we are hungry, all we have to do is open up the fridge and decide what we want to eat. On the other hand, when fish are hungry, they must leave the safety of their home to forage in areas where there are likely predators awaiting them. They must balance their decision based on hunger and risk factors: is this next meal worth the possibility of becoming prey? All organisms must eat to meet certain metabolic and energetic demands to survive. The metabolic rate of a fish is influenced by temperature because most fish … Continue reading

Re-evaluating the health of coral reef communities: baselines and evidence for human impacts across the central Pacific

Figure 1. (a) Theses images show hard coral and macroalgae, the two groups most often used to assess reef health. (b) These images show reef builders and fleshy algae, which can be used to assess reef-health with a more community-based approach.

By Shannon Moorhead, SRC Masters Student In the past several decades, it has become clear to researchers that populations of reef-building corals have suffered significant declines worldwide. In the 1970s, coral covered on average,50% of benthic habitat (the sea floor) in the Caribbean; in the early 2000s, this was reduced to an average of 10%, with an estimated 80% decline in total cover throughout the Caribbean. Similar observations have been made in the Pacific, with an estimated decrease from 43% coral cover on average in the 1980s, to 22% cover on average in 2003. These declines are caused by a … Continue reading

Marine Protected Areas Play a Crucial Role in Conservation and Fisheries Management

A cartoon by Jim Toomey illustrating the importance of marine protected areas.

By Abby Tinari, SRC Intern Marine protected areas (MPAs) are put in place to protect natural resources from anthropogenic impacts. They play a crucial role in biodiversity conservation and fisheries management, allowing for the protection of nurseries and breeding grounds for rare or commercially important species. Introduction MPAs attempt to maximize fishery yields while protecting against overfishing and fishery collapse. In turn, this aims to provide a sustainable market, as well as combat the negative evolutionary effects of fishing. MPAs have arbitrary borders; they are not permanent structures, fish can pass through the borders and therefore spillover into areas outside … Continue reading

Individual, unit and vocal clan level identity cues in Sperm Whale Codas

As seen above, a Sperm Whale (Physeter microcephalus) breaching. The head of the sperm whale contains a waxy like substance called spermaceti which it uses to focus and amplify the clicking noises used for communication and echolocation.

By Ryan Keller, SRC intern The social calls produced by sperm whales consist of three or more broadband overlapped clicks, called Codas. It is believed that certain codas are used to call certain individuals within a unit rather than a broader class of codas which are to all whales in the area. During social learning whales will “babble” and produce many indistinct codas before mastering the skill and eventually producing the specific calls much like a human baby making noises before learning specific words. In order to know what message each specific coda transmits further research needs to be done. … Continue reading

Analysis of a drop chain trawl as a method of bycatch reduction with squid, skates, and flatfish

The ground-gear rigged to the trawl net included rubber disks and rollers, designed to prevent the catch of any unintended benthic species.

By Brenna Bales, SRC Intern It is no secret that bycatch is a huge problem threatening the health of the oceans. Gillnets, longlines, and trawl nets often capture many more unintended species than what is originally sought after. In order to reduce this extremely wasteful practice, it is imperative that new systems and new technologies be created to find a solution. Here, Bayse et al. (2016) tested the viability of drop-chain trawls as a tool to reduce bycatch. Drop-chain groundgear, configured beneath a trawl net for this experiment, was determined to be effective at reducing bycatch in the Nantucket sound … Continue reading

Herring Perform Stronger Collective Evasive Reactions when Previously Exposed to Killer Whale Calls

Image 2_1200px-Killerwhales_jumping

By Shubham Mathur, SRC Intern The ability of large schools of marine fish to react to predatory behaviors with high levels of coordination. Forming a school and synchronized swimming are used to reduce the risk on any individual, and to detect approaching threats. The Atlantic herring (Clupea harengus) is an example of a species that forms large schools. Like many species of small pelagic fish, the Atlantic herring is a vital source of prey for many larger marine species, including fish, sea birds, and even marine mammals, all utilizing different methods of predation. As hunting pressures are never constant, the … Continue reading