MARINE AND FISHERY SCIENCES 34 (1): 109-112 (2021)

https://doi.org/10.47193/mafis.3412021010302

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

109

*Correspondence:

genzano@mdp.edu.ar

Received: 7 September 2020

Accepted: 27 October 2020

ISSN 2683-7595 (print)

ISSN 2683-7951 (online)

https://ojs.inidep.edu.ar

Journal of the Instituto Nacional de

Investigación y Desarrollo Pesquero

(INIDEP)

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Marine and

Fishery Sciences

MAFIS

NOTE

Kirchenpaueria halecioides (Cnidaria: Hydrozoa): a non-native hydroid in

the coast of Buenos Aires, Argentina

GABRIEL GENZANO*and PABLO E. MERETTA

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

110 MARINE AND FISHERY SCIENCES 34 (1): 109-112 (2021)

colonies collected in Madeira, Azores, and main-

land Portugal, mostly in ports and marinas. Thus,

we can infer that this taxon was dispersed

through boats.

Detection of non-native species varies across

regions and taxa. Hydroid faunal is well-studied

in the coast of Buenos Aires, Argentina (Genzano

et al. 2009). Particularly, in Mar del Plata har-

bour, SCUBA monitoring studies have been car-

ried out by authors from the early ’90 to the pres-

ent; therefore, we can confirm that the record in

2005 could represent the starting point of an

introduction of this hydroid in Argentina. The

finding of the species does not imply successful

colonization. However, subsequent records in

2006 and 2007 confirmed its presence in the area,

and the finding of mature gonothecae in colonies

in 2006 and 2016 suggested local reproduction.

Monitoring will be necessary to analyse

changes in its abundance and detect if the species

colonizes neighbouring areas or remain confined

to the port area such as many other non-native

species found in this particular habitat.

111

GENZANO AND MERETTA: EARLY INTRODUCTION OF K. HALECIOIDES

Figure 1. Kirchenpaueria halecioides. A and B) Colonies found in Mar del Plata harbour (scale 1 cm). C and D) Detail of mature

colonies and gonotheca (scale 0.25 mm).

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