Maritime mammals: terrestrial mammals as consumers in marine intertidal communities

Abstract

The phenomenon of terrestrial mammals as predators in marine intertidal communities, and thus as agents of energy transfer from sea to land, is poorly understood. We review here the evidence for terrestrial mammals intentionally entering the ocean shore at low tide in order to prey on living marine invertebrates, fish, algae, and seagrasses. We introduce the term 'maritime mammals', defined as coastal mammalian predators that utilize living intertidal energy resources and transfer these resources to the land. We document 135 records of predation among 45 species of terrestrial mammals in 8 orders feeding in marine intertidal zones. Most predation events are by carnivores (59%, mostly by raccoon, mink, black bear, and Arctic fox), followed by rodents (20%) and artiodactyls (14%). Maritime mammals occur on all continental coastlines of the world except Antarctica. Most records are from the Eastern North Pacific Ocean, with 21 species of maritime mammals. Twelve maritime mammal species occur in the Western North Atlantic Ocean, and 8 maritime mammals are known for the Eastern South Pacific Ocean. These 3 regions account for 42% of the diversity of maritime mammals. A total of 228 different prey taxa are known to be consumed, representing 12 phyla of marine organisms; 2 /3 of these taxa are bivalve and gastropod mollusks, crabs, and fish. Introduced populations of 17 species of mammals have been recorded as maritime predators; 15 of these are recorded on islands where endemic mammals were absent or rare. Maritime mammals are widespread globally, with often repeated cases of predation being observed for the same species. We suggest that predation by maritime mammals is a rarely studied, rather than rare, phenomenon, and maritime mammals are thus a largely overlooked guild of intertidal predators. Quantitative field observations (using techniques such as infrared night vision, radiotelemetry, and stable isotope analysis) and experimental studies (using exclosures, or by taking advantage of the removal of insular introduced mammal populations) are required. The importance of intertidal resources in supplying energy to terrestrial populations of many species of mammals world wide may have been underappreciated.

Ecology of freshwater shore zones

“…This guild includes predatory arthropods like spiders and carabid beetles (e.g., Polis and Hurd 1996;Kleinwächtler et al 2005;, insectivorous birds and bats (Gray 1993), scavenging invertebrates like dipterans, isopods, and grasshoppers (e.g., Backlund 1945;Behbehani and Croker 1982;McLachlan 1983McLachlan , 1985Bastow et al 2002), predatory and scavenging mammals (Moore 2002;Carlton and Hodder 2003), and others. This subject will be discussed in more detail in the section on accumulation and processing of organic matter.…”

Stable Isotope Research in Southern African Birds

“…Ben-David et al, 2004) to numerous "maritime mammals" that consume intertidal energy resources and transfer these resources to the land (Carlton & Hodder, 2003). The ability of birds to fly enables them to transfer nutrients between terrestrial or marine systems and depositions of guano are testimony to the large amounts of nutrients transferred from sea to land.…”

<b>The persistence of the Striped Hyena <I>Hyaena hyaena</I> Linnaeus, 1758 (Mammalia: Carnivora: Hyaenidae) as a predator of Olive Ridley Sea Turtle Lepidochelys olivacea Eschscholtz, 1829 (Reptilia: Testudines: Cheloniidae) eggs</b>

“…The occurrence of Striped Hyenas along the coast, though rarely mentioned, is known along the Red Sea (Foster-Vesey-Fitzgerald 1952) and the Kenyan coast (Carlton & Hodder 2003). The presence of the Striped Hyena Hyaena hyaena, a Near Threatened species (AbiSaid & Dloniak 2015), along Odisha coast, is particularly significant since the Odisha coast is vulnerable to several measures of climate change, particularly sea level rise (Kumar et al 2010) and severe weather (Kumar et al 2014).…”

“…Carlton & Hodder (2003) report the occurrence of Striped Hyena as a predator of intertidal fauna, such as crabs, along the Kenyan coast. While Tripathy & Rajasekhar (2009) suggest that hyenas may have excavated sea turtle nests, they do not clearly report a direct sighting of the animal or its feeding habits.…”