The Crook Laboratory at San Francisco State University is located in the Biology Building (Hensill Hall). Our animals are maintained in semi-outdoor, naturalistic seawater systems, providing sunlight and a natural day/night cycle. In addition to our research animals, we also maintain a large colony of live, planktonic food species.
Lab facilities include artificial seawater systems at three different temperatures (two tropical and one temperate), each with isolated tank zones for in situ behavioral studies. We have daylight, red-light and dark zones for studying animal behavior, and automated behavioural analysis software that tracks multiple animals.
Our Research Animals
Euprymna scolopes Hawaiian bobtail squid
E. scolopes is one of our core lab animals, meaning that we maintain a colony of squid in the lab, and they are used in many of our research projects. We raise our animals from eggs, and work with hatchlings, juveniles and adults.
Sepioteuthis sepioidea Caribbean reef squid
S. sepioidea is an occasional lab member. Caribbean reef squid have intricate mate choice behaviors and complex social interactions. We used these squid when we work on projects relating to plasticity in social behavior and mate contests.
Octopus bimaculoides Californian two-spot octopus
O. bimaculoides is a core lab member, meaning that we maintain a small number of animals in the lab year-round. We use bimacs for behavioral studies of spontaneous and hunting behaviors after minor injury.
Abdopus aculeatus Indonesian octopus
A. aculeatus is an intermittent lab member. This species is known for autotomizing arms when threatened. We use this species to study how neural responses to stimulation and defensive behaviors change after voluntary arm cast-off.
Our Cultured animals
Our lab maintains an extensive food chain that supports nutrition and culture of our research cephalopods. While we don't formally conduct research on these species, we focus on continual refinement of rearing and housing conditions to optimize their survival, growth and welfare.
Paeneus spp. Grass shrimp
We house several hundred grass shrimp in a naturalistic rocky-shore tank. Grass shrimp are the primary food source for our adult Euprymna and Octopus. These shrimp are native to Florida.
These females are carrying eggs, but we don't currently rear shrimp in the lab. We may conduct some studies on the sensory physiology of shrimp in future.
Mysidopsis bahia Mysid shrimp
Mysids are small, (<1cm length) estuarine crustaceans that are collected from Florida for our lab. Our mysids are the main food source for our hatchling cephalopods. Mysids breed readily in our tanks and we are working currently to create a sustaining culture of them in the lab.
Tisbe spp., Tigriopus spp., Acartia spp., Pseudocalanus spp., Diaptomus spp. Marine copepods
We culture multiple copepod species in the lab to feed our mysid shrimp, and to provide early stage nutrition to our hatchling cephalopods. The different copepod species have varying adult and juvenile sizes, providing our cephalopod hatchlings with size-appropriate food for their first two weeks. These Tigriopus copepods (pictured) are feeding on phytoplankton, which we culture in the lab.
Brachionus plicatilus Rotifers
Rotifers are the first animal in our food chain. We feed them phytoplankton that we culture in the lab, and they act as a carrier of the phytoplankton's nutritional content up the food chain. We feed rotifers to our mysids, our grass shrimp and directly to our 1- and 2-day old squid hatchlings. We are currently studying which phytoplankton species best supports sustained growth of our rotifer cultures.