Whale feces

Whales excrete plumes of liquid feces that are flocculent in nature, consisting of loose aggregations of particles. These feces, often found floating on the sea surface after being excreted underwater before it dissociates, contain undigested hard objects such as squid beaks. Fecal samples are characterized by color, odor, texture, and buoyancy, providing valuable information about the health and ecology of whales. Flatulence has been recorded in whales. ==Ecological significance==

{{Quote box Nutrient cycling and carbon sequestration One of the crucial roles of whale feces is in nutrient cycling, particularly nitrogen circulation in the ocean. Whales transport more nitrogen through their feces in certain regions than all the rivers combined, enriching both primary and secondary productivity. Additionally, the iron-rich feces of krill-eating whales encourage phytoplankton growth, benefiting the marine food chain and sequestering carbon dioxide for extended periods. The Southern Ocean, rich in nutrients but iron-deficient, experiences increased phytoplankton blooms due to whale feces, acting as a significant carbon sink. The phenomenon of whales defecating near the water's surface reverses the typical flow of nutrients in the ocean's biological pump, contributing to the "whale pump". Whales feed at deeper levels where krill is found, and their fecal matter, rich in iron, rises to the surface. This action enhances phytoplankton productivity and supports fish populations. Whales, along with krill, form a positive feedback loop, where their populations contribute to the recycling of iron, further boosting phytoplankton growth. A study in the Gulf of Maine extrapolated from modern levels nitrogen recycling in the sea due to marine mammals, such as cetaceans and seals, prior to the advent of commercial culling, estimating a former level thrice that of supply of nitrogen fixed from the atmosphere. Even today, despite reduction of marine mammal populations and increase in nitrogen uptake from the atmosphere and nitrogen pollution, the local clustering of marine mammals plays a significant role in maintaining the productivity in the regions they frequent. The Southern Ocean is amongst the largest ranges for phytoplankton and has the characteristic of being nutrient-rich in terms of phosphate, nitrate and silicate, while it is iron-deficient at the same time. Increases of nutrient iron results in blooming of phytoplankton. Whale feces are up to 10 million times richer in iron than the surrounding sea water and plays a vital role in providing the iron required for maintaining phytoplankton biomass on the earth. Accordingly, whales are referred to as "marine ecosystem engineers". A study conducted in the Fernando de Noronha Archipelago of the southwest Atlantic Ocean, revealed the feces and vomit of Spinner dolphins (Stenella longirostris) formed part of the diet of twelve species of reef fish from seven different families. The most prolific consumer was the black triggerfish or black durgon (Melichthys niger), which could even discern the postures dolphins assumed prior to voiding and positioned themselves for effective feeding. All these offal eating fish species are recorded plankton eaters and it is considered that this type of feeding may represent a change in its usual diet, i.e. drifting plankton. Whales, along with other large animals, play a significant role in the transport of nutrients in global ecological cycles. Population reduction of whales and other large animals has severely affected the efficacy of pump mechanisms which transport nutrients from the deep sea to the continental shelves. ==Whale feces as indicators of health and ecology==

Whale feces contain DNA, hormones, toxins and other chemicals which can give information on a number of aspects of the health, natural history and ecology of the animal concerned. Feces have also provided information on the bacteria present in the gastro-intestinal tract of whales and dolphins. Indicator for diet composition A 2016 research study used fecal analysis of wild orcas, which spent the summer season in the Salish Sea, for quantitively estimation of prey species. The analysis was consistent with earlier estimates based on surface prey remains. The study found that salmonids comprised over 98.6% of the identified genetic sequences with Chinook and Coho salmon species as the most important prey species. As indicator for population decline A research study, published in 2012, on impacts of overfishing and maritime traffic on a wild population of the Southern Resident Killer Whales of the western seaboard of North America, was based on the chemical analysis of fecal specimens of orcas. The study aimed to find out the reasons for orca decline for which three causes were hypothesized - disturbance by boats and ships, lack of food, and, long-term exposure of toxins which accumulate in whale fat, namely DDT, PBDT and PCB. Fecal samples of orca were detected with the help of a trained spotter dog, a black labrador retriever, named "Tucker", from a firm Conservation Canines. The dog could detect fresh scat from orcas while following in a boat behind a pod of orcas. Fecal samples collected were tested for the presence and quantity of DNA, as well as stress, nutrition and reproductive hormones, and toxins such as PBDE, PCB, and DDT congeners. The fecal samples were analyzed over time and co-related to boat densities over time and the quantity of Fraser River Chinook salmon, the main constituent of orca diet in those regions. Boat densities and the salmon abundance over time were estimated independently. ==References==