page_title: Sockeye salmon
section_title: Competition
hierarchical_section_title: Sockeye salmon / Competition
caption_attribution_description: Sockeye salmon get their famously bright red color and hooked nose after they return to freshwater to spawn. Bristol Bay is home to the largest run of wild sockeye salmon in the world - with an average annual run of over 30 million fish. This photo was taken on the Wood River, which flows into the Nushagak River just north of Dillingham, Alaska. Photo courtesy of Thomas Quinn, University of Washington Visit www.epa.gov/bristolbay to learn more about EPA's Bristol Bay Watershed Assessment.
context_page_description: The sockeye salmon, also called red salmon, kokanee salmon, or blueback salmon, is an anadromous species of salmon found in the Northern Pacific Ocean and rivers discharging into it. This species is a Pacific salmon that is primarily red in hue during spawning. They can grow up to 84 cm in length and weigh 2.3 to 7 kg. Juveniles remain in freshwater until they are ready to migrate to the ocean, over distances of up to 1,600 km. Their diet consists primarily of zooplankton. Sockeye salmon are semelparous, dying after they spawn. Some populations, referred to as kokanee, do not migrate to the ocean and live their entire lives in freshwater.
context_section_description: Aggressive behavior displayed by dominant males is predominantly directed towards intruding dominant males.  Sometimes sockeye salmon males behave aggressively towards subordinate males.  These encounters are short, with the intruding male leaving after one or two aggressive interactions.  Spawning females direct their aggression primarily towards intruding females or other spawning females that are close by.  However, they may also direct aggression towards intruding or subordinate males.  Aggressive interactions between females only last one or two charges and/or chases.  The intruder retreats and the spawning female settles back in her redd.  These acts of aggression are important in terms of reproductive success, because they determine the quality of the nest site the female obtains and access to males.
  Competition for food or space while the salmon are in their lake residence period can exist.  This happens when there is a more populous class of young sockeye or when there are multiple classes present.  It can also happen when resources are in short supply. Interspecific competition can also occur and can lead to interactive segregation, which is when species emphasize their differences in diet and habitat to avoid competition.  Interspecific competition can affect the growth rates of the salmon if their access to resources is limited.
caption: Male sockeye salmon
exif: {"Image ExifOffset": "2098", "Image Padding": "[]", "EXIF DateTimeOriginal": "2010:07:26 17:17:17", "EXIF DateTimeDigitized": "2010:07:26 17:17:17", "EXIF SubSecTimeOriginal": "65", "EXIF SubSecTimeDigitized": "65", "EXIF Padding": "[]"}