MARINE AND FISHERY SCIENCES 34 (1): 109-112 (2021)
ABSTRACT. Hydroid colonies are among the groups frequently carried and introduced by
human actions. Many species have been successfully transported as fouling organisms on ship hulls
or in ballast water (pelagic stages) and the sea harbours appear as the places with high probability
to detect exotic species. During routinely SCUBA diving conducted in Mar del Plata harbour,
Argentina (38° 08′ S-57° 31′ W; May 2005, December 2006, March 2007, and December 2016)
clumps of a plumularid were photographed and collected. Hydroid colonies were identified as
Kirchenpaueria halecioides, a species frequently reported in tropical and subtropical water from the
Southwestern Atlantic, Brazil. Records of mature colonies in 2006 and 2016 suggest local reproduc-
tion of this non-native species. Monitoring will be necessary in order to analyse if species colonize
neighbouring areas or remain confined to the port area.
Key words: Exotic, harbour, early introduction, Southwestern Atlantic.
Kirchenpaueria halecioides (Cnidaria: Hydrozoa): un hidroide exótico en la costa de Buenos
Aires, Argentina
RESUMEN. Las colonias de hidroides se encuentran entre los grupos transportados e introduci-
dos frecuentemente por acciones humanas. Muchas especies han sido transportadas con éxito como
organismos incrustantes en cascos de barcos o en agua de lastre (etapas pelágicas) y los puertos
marítimos aparecen como los lugares con alta probabilidad de detectar especies exóticas. Durante
el buceo rutinario realizado en el puerto de Mar del Plata, Argentina (38° 08′ S-57° 31′ W; mayo
2005, diciembre 2006, marzo 2007 y diciembre 2016) se fotografiaron y recolectaron grupos de plu-
mularidos. Las colonias de hidroides fueron identificadas como Kirchenpaueria halecioides, una
especie frecuentemente reportada en aguas tropicales y subtropicales del Atlántico Suroeste, Brasil.
Los registros de colonias maduras en 2006 y 2016 sugieren la reproducción local de esta especie no
nativa. El monitoreo será necesario para analizar si las especies colonizan áreas vecinas o permane-
cen confinadas al área portuaria.
Palabras clave: Exótica, puerto, introducción temprana, Atlántico Sudoccidental.
Hydroids, the benthic stage of the hydrozoans, present different strategies
for pelagic dispersion which include a planktonic sexual medusa (in species
with metagenetic life cycle) and a free-swimming larva (usually a planula);
but other dispersal strategies are present in the group which include disper-
sion by buoyant autotomised hydranths and tolerant or resistant stages
Received: 7 September 2020
Accepted: 27 October 2020
ISSN 2683-7595 (print)
ISSN 2683-7951 (online)
Journal of the Instituto Nacional de
Investigación y Desarrollo Pesquero
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International License
Marine and
Fishery Sciences
Kirchenpaueria halecioides (Cnidaria: Hydrozoa): a non-native hydroid in
the coast of Buenos Aires, Argentina
Estación Costera Nágera, Instituto de Investigaciones Marinas y Costeras (IIMyC), Universidad Nacional de Mar del Plata (UNMdP),
Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina
(frustules) detached from colonies. Besides,
colonies can live on rafting objects or as free-liv-
ing fragments floating in the water column which
provide another route for dispersal (Cornelius
1992, 1995; Bavestrello et al. 2000; Slobodov
and Marfenin 2004; Jaubet and Genzano 2011).
High growth rate, budding and the formation of
stolons allow hydroids to colonize space rapidly
and develop colonies on different types of sub-
strates including living-organisms (Genzano et
al. 2009).
Due to the mentioned characteristics, hydroid
colonies are among the groups frequently trans-
ported and introduced to new habitats by human
actions (Haydar 2012). Many species have been
successfully carried as fouling organisms on ship
hulls or in ballast water (pelagic stages) and the
sea harbours appear as the places with high prob-
ability to detect exotic species. In addition, this
environment can present greater hydrobiological
stability in relation to external waters, favouring
the feeding and growth of species.
Early detection of non-native species is a cru-
cial first step in effective management and risk
evaluation that these types of organisms can
cause. Rapid response actions can reduce the
long-term ecological harm that they could pro-
duce on communities.
During routinely SCUBA diving conducted in
May 2005 in Mar del Plata harbour, Argentina
(38° 08′ S-57° 31′ W) a small patch of plumularid
colonies were photographed, which was apparent-
ly different to that reported previously in the area
(5 m depth, 14 °C). During December 2006
SCUBA diving was conducted to collect these
plumularid. Two matures and two immature
colonies (7 m depth, 18 °C) were detached from
rocks and preserved in alcohol. Other clumps
were photographed during March 2007 (5 m
depth, 20.5 °C), and finally two mature colonies
were collected (5 m depth, 18.5 °C) and preserved
in alcohol in December 2016. Hydroid colonies
were identified as Kirchenpaueria halecioides
(Alder, 1859) (Hydrozoa, Kirchenpauriidae).
This species is easily recognized by the struc-
ture of the colony, the shape of the nematothecae
and the barrel-shaped, corrugated gonothecae
with a flattened top. Analysed colonies are erect,
10-20 mm high; the hydrocaulus is divided at reg-
ular intervals into internodes, each one bearing a
distal nematotheca and a hydrocladial apophysis,
alternate and bearing unbranched hydrocladia,
divided at internodes. Thecate internodes with a
distal hydrotheca, a median inferior nematotheca,
and a median superior nematotheca. Hydrotheca
cup-shaped, margin entire, central axis oblique to
that of hydrocladium, with a circular aperture.
Gonotheca is elongated oval, truncated at the dis-
tal end, with distinct transverse ridges arising by
a short pedicel from hydrocaulus. These morpho-
logical characteristics are according to the previ-
ous description of this species (see Peña Cantero
and García Carrascosa 2002) (Figure 1).
K. halecioides is a circum-tropical/temperate
species with great tolerance to hydrological fac-
tors as salinity and temperature. Its wide distribu-
tion is probably influenced by its presence in sea
harbours and regular occurrence as a fouling
organism (Peña Cantero and García Carrascosa
2002, and references therein).
In the Southwestern Atlantic the species was
found several times from shallow waters, rocky
intertidal to 73 m depth, on algae, barnacles, mus-
sels, hydroids, mud, mangle roots, rock, sand-
stone reef, shells and wood. All reports corre-
spond to Brazil between 7.50° S to 8.50° S, (trop-
ical) and 20° S to 27.50° S (subtropical) waters
(see Oliveira et al. 2016 for distribution and syn-
onymies in these regions).
Thus, our findings represent the early introduc-
tion of K. halecioides in temperate water for the
region, 1,160 miles southward to previous
reports in South America.
Some colonies collected by us during Decem-
ber 2006 in Mar del Plata harbour (Genbank
accession number haplotype # 386) were recently
examined by 16S sequences by Moura et al.
(2019), exhibiting the same haplotype with
MARINE AND FISHERY SCIENCES 34 (1): 109-112 (2021)