Adults also have paired, segmented sensory antennae. Crustaceans in general have various sensory resceptors, mainly setae over the body. Photoreceptors are also generally present.
Communication Channels: tactile ; chemical
Perception Channels: tactile ; chemical
The life cycle of Pennellidae species has not been fully studied. However, the typical copepodid life cycle is comprised of several stages, where there is a free-living stage within which the copepod undergoes several series of molts until the infective immature stage is reached. Also characteristic of this order is the existence of an intermediate host in the life cycle, usually a fish of some sort, but sometimes other vertebrates are used. The early development of the larvae takes place in the egg sac while it is still attached to the female copepodid, which then develops more and is ultimately released into the water possessing a full set of cephalic appendages and three pairs of thoracic legs. The copepod then finds its intermediate host where it remains until it reaches its later copepodid stages. After development of the attachment mouthparts, the copepod finds its definitive host where it then permanently attaches. Engorged females can produce from 300 to 700 eggs in each of her paired egg sacs.
Although the Pennellidae species do not have a direct effect on humans, they do have an impact on the whaling industry as they affect the exterior, and sometime the interior, parts of the whales. Infested whales tend to have scars and legions on the surface of their blubber.
The definitive hosts for Pennella balaenopterae are the Sei and Minke Whales (Balaenoptera borealis and Balaenoptera acutorostrata, respectively) of the Antarctic and North Pacific regions of the world. There have been some intermediate hosts found for species of the Pennellidae family that are important for the life cycle of the species. Although the intermediate host of Pennella balaenopterae is not known, this is not the case with all other copepodids.
Ecosystem Impact: parasite
Species Used as Host:
Pennella balaenopterae is an ectoparasite of whales. It feeds by siphoning blood from the host through its elongate mandibles, which are the parasite's primary mouthparts.
Animal Foods: blood; body fluids
Primary Diet: carnivore (Sanguivore , Eats body fluids)
Pennella balaenopterae is found in the Antarctic seas and the Western and Northern Pacific Ocean.
Biogeographic Regions: antarctica ; pacific ocean
The definitive hosts for Pennella balaenopterae are the Sei and Minke Whales (Balaenoptera borealis and Balaenoptera acutorostrata, respectively) of the Antarctic and North Pacific regions of the world. There have been some intermediate hosts found for species of the Pennellidae family that are important for the life cycle of the species. Although the intermediate host of Pennella balaenopterae is not known, this is not the case with all other copepodids.
Habitat Regions: saltwater or marine
Aquatic Biomes: pelagic
Pennella balaenopterae may reach up to 30 centimeters long, and thus is one of the largest species of copepods within its family. Adult females are characterized by a loss of external segmentation and obscuration of swimming appendages. Pennella species are recognized by the branched outgrowths on the posterior part of their trunks. The mandibles are prolonged, forming a sucking tube for the mouth through which the species feed. Adults also have paired, segmented sensory antennae. Five pairs of thoracic legs are found in the species, which are more modified in females than males. After attaching to the host the parasite undergoes diphasic growth. The first phase of this type of growth occurs in the copepod's anterior body portion. During the second phase of growth, the posterior portion, designated primarily for reproductive processes, begins to grow extremely rapidly, and is soon larger than the anterior portion.
Range length: 30 (high) cm.
Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry
Sexual Dimorphism: sexes shaped differently
This free-living stage of this species is likely eaten by fish or other copepod predators. Eggs and younger stages have a high mortality probably due to not reaching a suitable host.
Both sexes differ. Females have distinctive anchoring processes that extend from the anterior end of the parasite. Mating occurs after both sexes have reached full sexual maturity. After copulation, the copepod male dies early on in the cyclopodid stage of the life cycle. The female then loses all external segmentation and grows drastically in size. Both temperature and salinity are important factors to ensure successful reproduction.
Key Reproductive Features: sexual ; fertilization (Internal ); oviparous
Parental Investment: pre-fertilization (Provisioning)
Pennella balaenopterae is a large ectoparasitic copepod specialising in parasitising marine mammals. It is the largest member of the genus Pennella, the other species of which are parasites of larger marine fish.
P. balaenopterae is one of the largest species of copepods within the family Pennellidae, reaching up to 30 centimetres (12 in) in length. The adult females are characterised by a loss of external segmentation and absorption of swimming legs. Pennella species are recognised by the branched outgrowths on the posterior part of their abdomens. The mandibles form a sucking tube for the mouth through which the species feed and adults also have a pair of segmented sensory antennae. Five pairs of thoracic legs are found in the species, which are more modified in females than males. After attaching to the host the parasite undergoes diphasic growth. The first phase of this type of growth occurs in the copepod's anterior body portion. During the second phase of growth, the posterior portion which is where the reproductive organs are, begins to grow extremely rapidly, and is soon larger than the anterior portion.[3]
P. balaenopterae is found around Antarctica, and in western and northern parts of the Pacific Ocean.[3] It has also been recorded from the Mediterranean Sea.[4]
The sei whale (Balaenoptera borealis) and the minke whale (Balaenoptera acutorostrata) are the main hosts of P. balaenopterae. Most species of Pennella have intermediate hosts which are important for the life cycle of the species, but the intermediate host of Pennella balaenopterae is not known. There have been recent records of this species parasitising pinnipeds, namely a northern elephant seal (Mirounga angustirostris) in the north Pacific[5] and from fin whale, (Balaenoptera physalus)[4] Cuvier's beaked whale (Ziphius cavirostris), Risso's dolphin (Grampus griseus), the bottlenose dolphin (Tursiops truncatus) in the Adriatic Sea[6] and harbour porpoise Phocoena phocoena relicta in the Aegean Sea.[7] The early development of the larvae takes place in the egg sac while it is still attached to the female until it is released into the water column possessing a full set of cephalic appendages and three pairs of thoracic legs. The larval form then finds an intermediate host where it remains and develops into the copepodid stages. After development of the attachment mouthparts, the female copepod finds its definitive host where it then permanently attaches. Females can produce from 300 to 700 eggs in each of her paired egg sacs while engorged and attached to her definitive host. Males remain as free swimming copepodids but the females have a distinctive anchoring processes that extend from its anterior end. After both sexes have reached full sexual maturity copulation occurs, after which the male dies. The female then loses all external segmentation and grows drastically in size. Both temperature and salinity are important factors to ensure successful reproduction.[3]
Pennella balaenopterae is a large ectoparasitic copepod specialising in parasitising marine mammals. It is the largest member of the genus Pennella, the other species of which are parasites of larger marine fish.
