Dynamic Environments

San Pedro Bay is part of the Southern California Bight, a bend in the coastline stretching from Point Conception to Punta Colonet in Mexico. The Port Complex that includes the ports of Los Angeles and Long Beach encompasses more than 15,000 acres of land and water in the San Pedro Bay, and is protected from waves by a series of three breakwaters. Openings, or “gates,” in the breakwaters provide access to commercial shipping and also connect the Port Complex to the coastal habitats nearby.

The coastal waters of the Southern California Bight are influenced by a warm-water current moving north from the tropics and a cold water current moving south from Alaska. The mixing of these currents in the Southern California Bight results in high biodiversity, allowing species from both cold water and warm water climates to thrive.

Day/night cycles cue behavioral changes for many animals living in the Port Complex. As night falls, larval fishes and bait fishes such as anchovies move up toward the surface to feed on plankton. Larger predatory fish, such as mackerel, leopard sharks, and Pacific electric rays, are also more active at night as they hunt baitfish and prey on the seafloor. On the seafloor, animals such as lobsters emerge from their hiding spots to hunt for their prey, such as sea urchins, clams, and other invertebrates. 

Background image: Deploying a lampara net at night.

Come dawn, schools of anchovy retreat from shallow water, spending daylight hours in deeper areas of the Port Complex in order to avoid predation near the surface from birds, such as terns and pelicans, and marine mammals, such as sea lions. Small fish, such as juvenile topsmelt, will sometimes seek refuge under the docks and piers of the Port Complex, while larger fish, such as adult topsmelt and anchovies, may remain in the shallows, using kelp and eelgrass beds for shelter while they look for food.

Background image: Sunrise near Cabrillo boat ramp.

Tides also play an important role in the daily rhythm of life in the intertidal zone, with two low and two high tides per day in the Southern California Bight. Animals in the upper intertidal zone such as barnacles are exposed to the air for hours each day at low tides, while animals in the lower intertidal zone like mussels and oysters are only exposed during the most extreme low tides and only for short periods.  Animals in the subtidal zone, such as kelp, fish, scallops and sea squirts, are not as affected by the tides, while mobile animals such as sea stars can move throughout the tidal range to hunt for food.

Background video: Kelp bass hiding in giant kelp attached to a piling in the outer harbor.

Just as on land, the ocean experiences seasonal cycles that are driven by wind, waves, and the strength of the currents moving warm and cold water along the coast. The resulting changes in temperature, salinity, and nutrients affect the growth, movement, and abundance of plants and animals in the Port Complex.  

Background image: Ostrich-plume hydroids in the outer harbor.

Winter storms generate waves and wind that bring nutrients up from the deep ocean into the shallow coastal zone. As the water begins to warm in spring, these nutrients fuel tiny kelp that grow on riprap and pilings and phytoplankton growth that provides food for zooplankton, larval fishes, and a variety of small invertebrates. The kelp begins growing toward the surface, eventually forming the canopies of giant kelp that we see from the shore. Springtime also sees migratory visitors to the Port Complex, such as juvenile gray whales and their mothers feeding in shallow kelp and eelgrass beds as they migrate north from their winter breeding grounds.

Background image: Kelp canopy on the breakwater.

Summertime usually brings warmer, clearer water that promotes rapid growth of algae and eelgrass in the Port Complex. Some fish species make seasonal migrations, or ‘runs’, in order to spawn in these waters. California grunion are one such species found in the Port Complex that make their run in the summer, during which they will swim out of the water onto sandy beaches like Cabrillo Beach to lay their eggs during a high tide. Check out when the next grunion run is predicted to happen  here .

Background video: Rocky intertidal with ochre star, giant kelp and feather boa kelp in the outer harbor.

As summer turns into fall, ocean surface temperatures can become so warm that some annual species such as kelp and other algae begin to die back, the canopy kelp at the surface begins to disappear, and eelgrass plants die back. As the blades of algae and eelgrass die, they fragment, begin to decay, and fall to the seafloor where they become ‘detritus’, a valuable food source to benthic herbivores such as abalone and urchins, to filter-feeding animals attached to riprap and pilings, and to scavengers on the seafloor.

Background image: Eelgrass growing in the inner harbor.

The San Pedro Bay and the Southern California Bight also experience larger-scale variability that is tied into the greater oceanographic and climatic patterns of the Eastern Pacific Ocean. During hurricane season, Pacific storms that form in the tropics and make landfall in Mexico can create swell patterns that result in large waves when they reach the beaches of Southern California. While not all storms result in large surf, there are the occasional mega-storms like Hurricane Marie in August 2014; that storm created waves up to 20 feet high that delighted surfers but damaged the San Pedro Bay breakwaters.

Background image: Waves breaking on Cabrillo breakwater.

The Pacific Ocean also has cycles that occur on longer timescales, such as the El Niño/La Niña events that can result in warm and cool periods every few years. In 2014-2016 and 2019, unusual warm-water events, called marine heatwaves, occurred in the region. These are periods of high sea surface temperatures that can persist for months to years. Temperatures began to rise in 2014 and peaked in 2015, with temperatures 5-7 degrees Fahrenheit above average. When combined with long-term changes that stress marine habitats like global sea surface temperature rise, ocean acidification, and harmful algal blooms, marine heatwaves such as the one in 2014-2016 resulted in multiple fishery collapses, thousands of sea lion pups becoming stranded on the beaches, and declines in migratory bird abundances.

Background image: A satellite image of the 2014-2016 marine heatwave (sea surface temperature anomaly depicted in red) on the West Coast of the US.

The habitats of the Port Complex undergo constant changes, some lasting hours or days, others stretching for months or years. As climate change, sea level rise, and coastal development continue to stress coastal habitats, understanding the factors that affect biological communities on different temporal and spatial scales is vital for their protection. The ongoing Port of Long Beach and Port of Los Angeles Biosurvey program ensures that scientists are monitoring these habitats and the animals that live in the Port Complex to determine if changes to the biological communities result from environmental factors or human causes. These robust monitoring efforts show that the vibrant marine environment continues to improve as programs enacted by the two ports result in improvements in harbor water and sediment quality, protect aquatic wildlife, and ensure compliance with laws and regulations governing water quality, wildlife conservation, and habitat mitigation.

Background video: Diver performing a survey in the outer harbor to determine the percentage of riprap covered by different types of algae and animals.