This is the last part of the dolphin series. History Animals have been held in captivity by humans for thousands of years. almost every species of marine mammal except for most of the great whales have been held in captivity, even if only for short periods of time. Most of them are dolphins, porpoises and …
Tag: dolphins
Dolphin series: monitoring dolphins
For the biologist, dolphin research presents challenges and opportunities in trying to understand individual species in their marine ecosystems. Marine mammals are highly mobile, cover large areas, move in three spatial dimensions, and spend most of their lives under water. So for most species of delphinids, basic aspects of their evolution, physiology, ecology, behavior and …
Dolphin series: fishery interactions
Fishing intensity keeps increasing throughout the world, which has negative impacts on nontarget species, including marine mammals. Thus bycatches have become a critical issue for marine mammal populations. Every year fishing industry removes about 80–90 million tons of fish and other marine organisms from the world’s oceans. Another 7–8 million tons of unwanted animal biomass …
Threats to dolphins
Dolphin mortality results from both natural and anthropogenic causes. Natural causes include old age, failure to thrive as a calf, intra-specific agonistic interactions, predation, stingray wounds, disease, storms and biotoxins from harmful algal blooms such as red tides. Threats of human origin include entanglement in nets, entanglement in or ingestion of fishing gear, pollution, boat …
Dolphin behaviour
To research dolphin behaviour we first have to ask the question: what is the problem the behavior has evolved to solve? The following is a list of some of the main problems: foraging: how to find, select, and process prey; predator avoidance or defense: the flip side of foraging from the prey’s point of view; …
Photo identification in marine biology
Definition in marine biology: the method of study of marine mammals using photographs to identify individuals. We will particularly concentrate on dolphins and how we rely on the presence of unique natural features, specifically on the dorsal fin (the size and location of notches and cuts), to identify individual animals. Natural markings data can be …
How dolphins sleep
First of all, dolphins do sleep, but it’s not the type of sleep land mammals have. Dolphins are conscious breathers, which means they have to think about when to go up to the surface and take a breath. Since they don’t breathe autonomously and have to plan every single breath, they undergo a form of …
How dolphins communicate
Dolphins keep a complex social network which includes a few close associates (such as mothers and calves or pair-bonded individuals) and some more casual relationships within a larger group. Dolphins hunt together for food, pods coordinate their movements to herd prey. They have a very acute sense of hearing which they use to communicate with …