Common bottlenose dolphins are the largest species of the beaked dolphins that inhabits in temperate and tropical oceans worldwide. These species are large that mostly found in groups and known to mixed with other species like whales and cetaceans. Common bottlenose dolphin diet mainly squid, eel, shrimp and wide variety of fishes by swallowing a whole than chewing it. Dolphins usually search prey using echolocation in a form of sonar. And uses sounds for communication like squeaks emitted from blowhole, whistles from nasal sacs and body language. The coastal of United States Pacific is known to have around 450 individuals while the offshore population about 3,495 individuals. In Canadian west coast no common bottlenose dolphin has been documented. However, on July 29, 2017 a sighting of this species mixed with cetaceans and killer whales has been observed.
Common bottlenose dolphins observed in Canadian waters
For the first time common bottlenose dolphins have been observed on July 29, 2017 in Canadian water. Each individual shows particular characteristics like short to moderate beak. A curved mouth line that dips downward resembling like a smile and tall falcate dorsal fin at the central back. Moreover, the body colors were usually light grey to black on the back and side while light to white color around the belly.
The sighting of the large group of common bottlenose dolphins is the first confirmed occurrence in Canadian Pacific waters. The location of sighting is approximately 1000 km northwest coast of America which signifies the first northernmost record of the species. About 200 dolphins were seen in the group in an unusual large aggregation. On the other hand it was also observed that this dolphins traveling closely with false killer whales, a typically offshore species.
The discovery of common bottlenose dolphins and false killer whales signifies the warming trends in North Pacific waters. Both of the species typically inhabit warm temperate waters in lower latitudes. But this sighting indicates that British Columbia, Canada oceanic conditions gives suitable habitat for them. It is also recorded that the show-up happened after a prolonged warming period.
Source: Prepared by Joan Tura from Springer Nature BMC Marine Biodiversity
Vol. 11: 3, 20 April 2018
Microplastics are less than 5mm diameter particles that came from different sources including cosmetics, clothing and industrial processes. This synthetic particle also originates from shipping spills, polystyrene beads and fishing gear. It is widely distributed in the environment particularly in aquatic and marine ecosystems. Microplastics classify in two, first it came from direct result of human material and product used. Second it derives from the breakdown of larger plastic debris. Because microplastics do not break down for many years, it is then ingested to aquatic and marine mammals in particular. Hence, the interest of this research study is to understand the impacts of this vast microplastic on marine ecosystem. As well as on the effects of organisms health that live on it.
Ingestion of Microplastics by large Mammals
The investigation of microplastics shows an empirical evidence of the trophic transfer from fish to marine top predator. There were 12 polymer types have been detected in fish and seals wherein ethylene propylene is the most common. And the polymer found in seals varies into almost ten types maybe because of the diversity of the marine environment. The study also indicates the variations of color and sizes of microplastics detected in fish and seals. Wherein blue, red and black colors are more prominent. As a result significant range of microplastics abundance, type, size, color and polymer types are not observed only among fishes. But within the marine environment in general wherein different kinds of species thrives in.
In addition detection of microplastics depends on the process of extraction as well as coloration. Since transparent particles are less obvious because of its translucent substrate. It also indicates that harbor seal contains more plastics in stomach suggesting that non-food items trap inside especially microplastics. Indeed, the research reveals strong correlation between polymer type in both fishes and seals. Thus, signifying that the microplastics found in seals is a consequence of ingestion rather than inhalation. Also it attributes the presence of microplastics particles in seals to the amount of trophic transfer from prey to marine top predator.
Therefore, the current study presents an empirical evidence of microplastics transfers across trophic levels from fish to top marine predator mammals. It is also found out that trophic transfer represents an indirect yet a major pathway of microplastics ingestion to any species. By which the feeding mechanism is through the consumption of the whole prey including humans.
Source: Prepared by Joan Tura from Environmental Pollution
22 February 2018
My work as a marine biologist has drawn me to the Coral Triangle, an area of our oceans consisting of the highest levels of marine biodiversity. You can imagine that the abundance of marine life led to a high reliance of local populations on seafood. It is a cruel irony that some of the methods used to harvest this seafood destroy the very foundations of seafood supply. So when I decided to hop on the Conservation bandwagon, the Coral Triangle was an obvious choice. (more…)
Welcome to guest blogger, marine biologist Sam Craven, from Mad As A Marine Biologist.
As a marine biologist and a diver I feel incredibly privileged to have seen many of the delightful examples of life that the most biodiverse ecosystem on our planet, the coral reefs, have to offer, but nothing has kept by attention and enthusiasm as much as the group of shell-less molluscs, the nudibranchs. (more…)